December 18, 2021

Miscellaneous Mail and Frequently Asked Questions

These are a variety of questions I have been asked that did not fit into the other categories.

Other Mail and FAQ Pages

I've built a couple of kits and think I'm ready for try at a scratch build project. Can you recommend a good starting point? Plans, etc? I think I have most of the basic tools (your site helped me there).

My recommendation for a first scratch built is a Stik. They’re as simple as a plane can get. You don’t need many tools. The bottom of the fuselage is a straight line and the wing is constant chord. They can be relatively tame (a good 2nd or 3rd plane) and still be sporty for more advanced pilots. They’re one of those planes that are very reliable if built right and when you’re too stressed to fly a more expensive plane they’re just the ticket. Stiks are great every day planes.

People keep writing me asking for plans but that means they’re missing the point. You don’t need plans. If it looks right it is. Stik moments range all over the place. If you really don’t know where to start then make a wing with a 4:1 to 5:1 aspect ratio. Make the fuselage 75% long (firewall to tail post) of the wing span.

Make the elevator+stabilizer area 20% of the wing area. Make the fin/rudder so it looks right. Make the tank compartment about 75% the length of the tank (some of the tank will be in the radio compartment. Mount the landing gear so the axle is about even with the leading edge of the wing when the plane is level. That’s assuming a tail-dragger. If you want to make a trike gear then mount the main gear about about 75% of the chord back from the leading edge.

Those are just ballpark figures. It’s really hard to go wrong with a Stik as long as you keep it within reason. Again, if it looks right it is so seriously don’t stress about the numbers. Just build it square, don’t over-build and keep it light but don’t go overboard there either and make it fragile.

You mentioned in your article under Basic Trigonometry: Trigonometry for Model Aircraft Builders that, "Algebra is excellent for finding the missing answer. For example, if you scale a plane with a wingspan of 60" and a chord of 9-3/8" to have a span of 72" then Algebra is the most efficient way to find the new chord."

Would you give me more detail as to how I would accomplish this? I'm very interested in learning how to scale up an aircraft from any set of drawings. Again, thank you for all that you're doing to help us. God Bless!

It’s called one equation, one unknown. What you do is solve for the one unknown by working the equation so it’s all by itself on one side of the equal sign.

Divide the new span by the original span. That will equal the new chord divided by the original chord (the one unknown).

72 / 60 = New Chord / 9-3/8”

Anything you do to one side of the equation you have to do to the other to keep it equal.

For example, if you add 2 to one side you have to add 2 to the other:

3 + 3 = 6

Add 2 to both sides:

3 + 3 + 2 = 6 +2

Both sides are still equal. Same thing goes when you multiply, subtract or divide.

Multiply both sides by 9-3/8 to isolate the new chord:

9-3/8 x 72 / 60 = New Chord

New Chord = 11-1/4”

The easy way to do it is just divide the new span by the old span and that’s your multiplier:

72 / 60 = 1.2

So all measurements from the original will be multiplied by 1.2 to find the scaled size.

If the fuselage is 40” long then multiply it times 1.2 to find the length of the new fuselage (48”).

Hi Paul, I wanted to drop a note and say thanks for all the great articles you've posted on building techniques and philosophy. My interest started when I was a kid in the 50's and my Dad built and flew U/C. As usual, life got in the way for both of us. I got him started again in the 70's when I got involved in slope soaring. He's still building and flying today at 86.

I had to take a 30 year break to make a living. Your site provides a lot of good ideas and inspiration to keep me from my cut and fit SWAG (scientific wild-ass guessing) approach. I spread the word at the local flying clubs about your site for the builders still out there. Sorry that you had the problem keeping the website up. That's the second reason I'm contacting you. Our club just made the decision to register a domain name for our own website to try and help draw in younger members. We have/had a website that one member set up on space provided by his ISP. I was hoping you might be have some insight as to the problems you've run into maintaining a web presence.

A web site is easy until you want your visitors to interact and you need scripting. Then you have to create some type of scripted pages using a database back-end and whatever language you want to script in. The most popular language is php because it’s free and secure. Almost every web host supports it.

mySQL is the database used most commonly with php and is also free.

The problems start when your web host disappears or you want to move your site for whatever reason. All my hosts had my mySQL databases on a ‘mssqldb’ server. That’s how my personal computer is set up so I could write my pages and then make sure they work properly before uploading them.

My new host has a different named server (I didn’t know it was something to ask about, but next time…) which is why my site has been broken for months and I’m just getting it fixed. But the problem is that I can’t rename my computer from mssqldb to the new server name — at least I don’t know how to do it if I can. So I can’t debug any more. I have to upload the page and then test it. That means if I find a bug, anyone viewing the page will have the same problem... not very professional.

Additionally, I had to go back through every single page and change the word, mssqldb, to the new server name. Every time I thought I had them all I found more.

Here are my best general recommendations for your web site. Note I’m not a web expert. I learn things the hard way.

Stay away from flashy crap. All that is for is people who don’t have any real content and they want to disguise it by putting junk on their site that is cute once and then just annoying.
Say what you have to say and take a stand. Don’t try to please everyone. If you have an opinion just state it. People will give you more credibility than if you’re constantly trying to appease everyone. Some people just won’t agree with you and they may be right. Don’t worry about it. That doesn't mean don't learn though.
Make your pages viewable at any resolution. My pages are a series of tables that aren’t any specific width. The left side is fixed for the buttons, but the content cells will always be the width of the screen. I really don’t like sites that have the text down a strip in the middle that means I have to keep scrolling even though 75% of my monitor is blank.
Don’t try to trick search engines. Use only keywords that are in the page body text (visible to visitors) or in the page title. If you use words that aren’t in the body or title then search engines will rank you lower because they think you’re trying to spam them. That’s what porn sites do — use keywords having nothing to do with what’s on the site (automobiles, home construction, student loans, etc.). When search engines find you doing that they sting you.
The page title is more important than the keywords. Put as many distinct keywords as possible in your titles and try to use the longest version. In other words say, “Building” not “build.”
Read up on web search engine optimization to learn the rest. It’s important if you want visitors. My site was online for 2 years and I was getting X visitors a day (about 15% of those visitors are indexing bots – good things). I read up on how to optimize my site for search engines and did serious revisions. Within 2 months the site had doubled that number. I fully believe it was because of the effort I put in to make the site search-engine friendly. Also note that the more content you have the more likely you are to be found by somebody searching for something. So don’t be stingy with the words. Write a lot but break up the pages so they aren’t too long. I still have some “too long” pages but I like to keep them to scrolling no more than 2 pages past what you see when you go to the page.
Oh, last but not least, get real hosting. Don’t use anything free because they put banners and ads all over your site. Visitors don’t stick around when the site is cluttered with crap.
I use FrontPage to create my pages because I can’t read or write HTML. But the themes that come with it are really cheesy. I spent many hours using a paint program to come up with the theme for my site. I spent many more days creating the buttons. Once it was all done and I was happy with it I saved it as a template page that doesn’t get uploaded. Then when I have a new page to write I just copy the template and rename it. Everything is in place already. Otherwise I would spend the first three hours just recreating the theme.
There are other WYSIWYG editors available. A lot of people don’t like FrontPage, but frankly, I think it’s the same guys who don’t like anything that is easier than what they learned. I’ve had no problems with it. But do note that if you use any FrontPage features beyond basic HTML your host will need to install FrontPage extensions for it to work. If you don’t want to use the features or your host doesn’t support it then that’s not a problem. Just don’t use that stuff.
Always check that your pages look and act right with both Internet Explorer and Netscape. 90% of everybody uses one of those two browsers. If you want to make your site compatible with other browsers then you’ll do 90% of the work for 2% of the visitors. Same goes for search engines. The top engines are Google, Yahoo, Lycos and a few others. Just pay attention to the most important ones. If you follow their rules then you’ll get more visitors and other search engines should follow the same guidelines.

I've heard that 'toe-in' is required with retracts. What does this mean?

Toe in means that viewed from above each gear wants to steer toward center by a small amount (1-2 degrees). The left gear would be pointed to the right and the right gear would be pointed to the left.

Toe-in is useful for helping the aircraft track straight when taxiing and on the take-off run. It helps the model correct itself if it starts to tip a wing. It doesn't help a lot so don't expect much but a little is better than nothing.

I'm trying to plot an airfoil and do not understand how you got percentage to inches to make ticks for marking stations along the center line of wing rib.

Multiply the chord of the rib by the station. For example, if the station is 9.8% (or .098) and the chord is 11.00” then multiply 11 x .098. That will give you the location aft from the leading edge of the wing.

Then you multiply the ordinate at the station by the same number (.098) to find the distance up or down from the centerline of the rib.

I was wondering if and how you did weight and balance on your designs. Maybe they're on your website but I didn't see this. Your step by step procedure is excellent. I commend you for your work.

If your question to me is how do I determine weight and balance in advance, then the answer is that I don’t. Based on my experience, I select materials that are as light as possible and also strong enough to do their job. When cutting symmetrically opposed pieces I try to always cut them from the same piece of wood so that I can avoid adding ballast.

If you’re asking about Center of Gravity placement, the range for most RC models is very forgiving. I usually start with a location about 5% farther forward than where I think it should be just so that if I’m wrong the plane won’t be uncontrollably tail-heavy. That’s worked well so far as I’ve never lost a plane or even damaged one due to improper CG placement.

I dial in the CG through flight testing. As far as engineering goes, I don’t have a degree or any book knowledge of the science. I’ve learned through trial and error.

A friend of mine has been flying models for many years, has also built 100's of models from scratch and does a great job. He has trouble finding some parts to rebuild planes after they are crashed. At the present time he is seeking a canopy and wheel pants for a 1/4 scale Pitts. Can you make any suggestions where he may be able to get these?

I have no idea where you can get the parts you need. You could try Fiberglass Specialties or Stan’s Fibertech for the cowl.

Another thing you can do is find a manufacturer who makes a 1/4” scale Pitts and purchase replacement parts.

Lastly you might try contacting some plan manufacturers and see if they have a 1/4 scale Pitts and where they say you can get the parts from.

You have convinced me to build my first trainer. I've done a lot of research on beginner airplanes and everyone has said the same thing: Get a .40 trainer.

The only thing is any airplane with an engine bigger than a .25 is a big no-no for me for various reasons (storage space, for example). Your Great Gonzo has proved that it can be an excellent trainer. So, the question is, can I get a .25 trainer kit and make the wing span a little longer so that it's even more stable?

While agree with those who have said a .40 size trainer is best, if a smaller trainer is your only option then that’s what you have to go with.

I believe that there is a .20 size Telemaster sold by Hobby Express and I also think that Sig Manufacturing makes an LT 25. Either would be good choices for a .25 engine.

I do not suggest that you redesign the models – they’re good as they are.

When building your trainer, keep it light by using glue sparingly and lots of sandpaper. Wipe up glue drips and glue that oozes out of joints, for example.

Appropriate Training Aircraft for Radio Control

I have been building planes for many years but never have flown one of them. The current project is going to be the one! I went and got one of the flight simulators so when I do finally join a club and take to the air I'll have a better than average chance of not crashing too bad. Are they realistic to actually flying?

I’ve never used any of the flight sims intended to teach R/C flight so I am not qualified to answer this question. I won't let that stop me though.

My gut feeling is that flight sims have some use, but are mostly over-rated. Where they should be helpful is with learning to orient the airplane and learning to work the controls when the plane is coming toward you.

Other than that I doubt the flight dynamics are very realistic. The military spends millions of dollars on sims so that the flight dynamics are realistic. I doubt our hobby has done the same thing.

Recently I have started to build a Radio Control model Airplane. For that I have initially started to collect the reference materials. If you have the design specifications for the model aircraft from start to end, please help me out in this regard.

I'm sorry, but I don't have this information for you. It would require a book or two to cover thoroughly.

Andy Lennon wrote a book about model aircraft design. I don't remember the title, but I'm sure if you search for his name at amazon.com, you'll probably find it. Also check out The Aircraft Proving Grounds.

I don't know if the site covers all of what you want, but it has a lot of good information.

The best thing I can tell you is to build a lot of models. Pay attention to design techniques and try to learn all you can.

I'm an Aerospace student and I'm planing to build a retractable landing gear. Can you help me with any kind of info on it such as what components I need and how to go about building the gear?

I've never built a retractable landing gear. I've always used commercially available units. Try Robart Manufacturing for more information. They also make custom gear. Maybe if you talk to the right person you might get some pointers on making your own.

What would you do with 120 static models of poor/mediocre/ho-hum quality?

I can’t answer this for you. When my skills got to the point that my earlier models embarrassed me, I tossed most of them out. I had a friend who wanted them, but for reasons of pride I did not give them to him because I didn’t want him to tell anyone that I had built them.

Some of the models were used to practice weathering/painting techniques on. I didn’t have nearly as many models as what you mention. I’ve moved around a lot and most of what I’ve built was destroyed during one move or another, so my collection never got to be very extensive.

There may be something charitable you could do with these models, but I don’t know what. If I were you, I would hang on to them until I was sure that I wouldn’t regret any decision I made.

By the way, I found a way to transport plastic models so they will not get broken. I will be posting a how-to on the site soon regarding how to pack delicate plastic models so they can survive a move.

In your field safety you strongly urge not flying alone for a beginner. Would you soften your position if:

1: The plane is a slow-flyer electric?
2: I have spent many hours reading 'flight-training' and appreciate that in many situations the appropriate action is not intuitive.

I understand that some of the small electric planes are much less dangerous than other types. However, my recommendation regarding having an instructor is not just for safety purposes.

There are several reasons why I recommend enlisting experienced help.

First, an instructor can check out your plane and ensure your aircraft is ready to fly. Often the instructions that come with the plane tell you what to do but not why you should do it.

In that regard, you may have followed the instructions, but still have the plane set up wrong because you don’t have the experience to understand the finer points.

Second, as you stated, some situations that are easy to get into require fast action to get out of. For example, it is easy to become disoriented and think the plane is heading in one direction when it is headed in a different direction altogether.

If you really want to go it alone, take a good look at your plane and honestly assess a worst case scenario. For example, imagine your plane hitting a person in the face.

If you can honestly say that the plane is harmless and you don’t mind losing it in a crash on the first flight, then it’s really your choice to go for it or not.

In any case, I strongly recommend that you find a wide open space where there aren’t people. The last thing you need is to be distracted by people asking you questions or being forced to have more piloting skills than you might have at this point (to avoid hitting somebody).

It would also be a good idea to have somebody with you to keep a lookout while you fly to let you know if anyone is entering the area.

The bottom line is that I strongly recommend that you seek help instead of attempting to fly an R/C plane on your own.

I am installing a RAM Nav light system in my airplane that uses a 9v batter to power it. I have an old on/off switch that I want to use to operate the thing (not servo activated). Will the switch work with the 9v, and which of the 6 connectors on the bottom of the switch do I hook the + and - to? Thanks for your help and thanks again for your great site. It has saved me many hours of re-building time.

Unfortunately, electronics isn’t my strong point, but a switch is a switch as far as it allowing power to flow through.

I’ve used some switches as you describe and the way I figure it out is to connect the negative lead directly to the voltmeter negative and hook the positive from the battery up to one of the posts on the switch.

Now check the positive lead from the voltmeter on each of the remaining posts and press the switch.

If the voltmeter registers when the switch is on and no power when it’s off, you’ve found a post that will work.

Chances are there is more than one post that will work. The worst thing that will happen is you won’t get power, but you won’t short anything either.

I read on your adhesives page that you recommend Carpenter's glue for general construction. Do you think I should use Carpenter's glue to build my plane with?

This is a trick question, right? I get this type question for many of the pages on my site, and to be honest, it confuses me. If I make a recommendation on the site, then I am going to make the same recommendation if you e-mail me and ask me if I recommend what I already have recommended. This applies to anything you read on this site.

Yes, I recommend Carpenter's glue for general construction of wood models.

I was wondering if you had any experience with mounting a camera on a radio controlled helicopter? I want to do this with a miniature 2.4Ghz type camera so I can see live back down to the ground and do basic fly by's of objects. Is there a lot of vibration on a copter? Would a soft mount solve this? Any info appreciated.

I don’t have any experience with mounting a camera on any type of aircraft. However, I did come across videos from a camera mounted on a helicopter on the internet a couple years ago. They looked pretty good. There was some vibration, but it wasn’t objectionable. If you get your heli set up right, there isn’t much vibration. Also, I’m not sure of this, but I think heli’s smooth out a lot in forward flight.

I suggest you post your question at RunRyder (an R/C helicopter forum) or RC Universe. There is surely someone there who has done this who can give you first hand advice.

Just a note of thanks for your nifty website and a request that you post a little info on Field Boxes. I do not mean what's in them, but the style you like best. Although I have seen quite a few, I feel there is room for improvement in all of them. I would be interested in reading your thoughts on the subject.

Typical Flight Box I really like to give straight-forward answers to questions whenever possible. However, this is one of those times that I have to ride the fence. Your field box should be designed around what it needs to carry which is both dependent on the type aircraft you fly and the type of person you are.

For example, we've all seen people who tinker endlessly on their planes at the field. I have even seen people who partially build their planes at the field which leads me to believe they do not have a shop at home.

I am of the mind that the flying field is for flying and the shop is for tinkering. That is why they call it a flying field and not a field shop.

Before I go to the field (usually the night before) I pre-flight my planes at home to ensure everything is in place and working properly. When I arrive home from the field I try to make immediate adjustments, repairs or whatever is needed while it is fresh on my mind. When I arrive at the field, all I need to do is assemble my plane, do another pre-flight, range check my radio and then fly.

What this comes down to is that I believe less is more. I do not have duplicates of most of my tools, so I carry a small tool box that contains screwdrivers, wrenches, etc., but I leave it in the car. All I take to the flight line is the model, my flight box and transmitter.

I leave the tools necessary to assemble the plane (usually one Allen driver or screwdriver) in the flight box. I do not carry glue to the field. If something breaks on a plane, I fly another and fix the damage in my shop - no exceptions.

However, a beginner should take anything and everything to the field. Invariably, parts of their planes are missing or damaged and a lot of work is necessary to get their planes in the air. As you get more experience and more proficient, tools and parts should start being left behind. Get into the habit of going to the field prepared. I do not like loading and unloading my car. I mean I REALLY do not like it, so less is more.

I agree that no flight box is going to be right for anyone. They are all very general in their design and construction. I also do not like plastic as they start looking ratty pretty quickly. So the bottom line is that a field box that can carry your fuel, starting equipment, a small First Aid kit, cleaner and towels and only the necessary tools to assemble your plane is as much of a field box as I recommend.

Mine could be a little better than it is, but it is as close to a perfect field box (for me) as I am going to get. It is small, light and carries everything I need.

By the way, in the picture above you can see the cradles that came with the box. I generally do not use them. Mine are stashed somewhere in my shop in case I ever do. In the drawer is my glow igniter, First Aid kit, a couple spare rubber bands for attaching antennas and an Allen wrench for the wing bolts. In the top is my electric starter, a couple diaper rags and spray bottle of cleaner. I use a manual fuel pump that is not shown, but it is attached to the right side of the box using double-sided foam tape.

Equipping a Flight Box

Why did not you answer my e-mail?

I try to answer every e-mail I get. I go through periods when I get swamped with e-mails and occasionally one gets lost in the shuffle. However, it is more likely that my e-mail got returned either because you are using some type of anti-spam software or your server is and my e-mail got rejected.

I would like to see some information about R/C cars on your website.

OK, here's everything I know about R/C cars...

R/C cars exist, some people have them and there is more than one kind and more than one size. They have gas or electric motors.

I like to stay in my areas of knowledge which does not include cars, so you will not read anything more about them at Airfield Models.

How do you dispose of solvents?

I know there are places you can take them to have them disposed of properly. I do not know what those places are. However, I never dump paint or solvents. Anything of this nature that I want to dispose of, I put in an open glass jar and allow to evaporate. If it is paint, then after it has hardened, I throw it away.

Why does not Airfield Models have a community forum?

There are several reasons I have elected not to have a forum. The main reason is that I believe too much of anything thins the waters too much. In other words, a large number of forums will result in a smaller knowledge base in any given forum. There are already some great forums for modelers and I do not see how I could offer anything different or better than what already exists.

The second reason is that I have some good friends who have successful forums. Without exception they have told me that having a forum is almost a full-time job. I am short on time already and simply am not interested in this type of endeavor.

Two forums I recommend are RC Universe and RC Groups.

I am building a Ziroli plans 100" wingspan Dauntless dive bomber and I would like to know if anyone manufactures four bladed props for world war two military aircraft models. I have seen a lot of beautiful models and the single blade props detract from the authenticity of the aircraft.

The only four blade props I have seen are carbon fiber. Most guys carve or make molds for display props for their scale models, but fly with a normal two-blade. I don’t know of any functional scale four-blade props that you can buy. You might try asking at RC Universe.

http://www.rcuniverse.com/

I am from India. I would like to learn model airplane building. Can you please suggest an academy or individual with whom I can learn to build good models - some place I can learn to make flying models with balsa and foam and composites? I would greatly appreciate help in this matter.

As far as an academy goes, I really don’t think there is an academy that teaches model-airplane building. If there is I’ve never heard of it. I only know one person in India and he's not a model builder. As far as resources go the best thing I can tell you is to search the internet and go to www.rcuniverse.com. There are a lot of people there who can answer your questions. You can also feel free to ask me specific questions about whatever project you’re working on.

Other great resources are the modeling magazine. Many magazines are steering more toward ARF's and do not have as much building-related content as they used to. Check out magazines devoted to scale builders even if you are not interested in scale models. They often have valuable building techniques that will help you. Another excellent magazine is Flying Models. It has a high percentage of content that is useful to builders. Most magazines have How-To articles as well as tips sent in by readers.

If you really aspire to be a great model builder there are a couple things that are absolutely necessary:

First, you have to enjoy building. That means not being in a hurry to finish the project, but enjoying working on it no matter how long it takes.

Second, there are no short-cuts. You can either decide to build as well as you can or you can try to find ways around it and end up with a lesser quality model.

The idea here is to enjoy the journey as much as or more than the destination.

It takes a lot of experience to really build well. I can tell you to make sure a part fits, but that’s easier said than done. It’s your personal experience that will tell you when to sand by hand and when to use a machine, which method will cut the part the most accurately, etc.

Make sure everything fits before you add glue. Sand everything – even parts inside the model that you’ll never see again. First, it makes the model better even if you can’t see it. Second it gives you just that much more experience.

Work on simple projects at first. It will give you more confidence than if you take on a project that is too difficult for you then you’ll become frustrated and feel that you will never get better. Well, you might not get better if you quit because what you are building is beyond your capabilities.

I suggest you build Sig wood kits. Start with their trainers and work your way up. They all fly well because Sig actually takes the time to develop their models and get them right before releasing them. Each model is designed to advance your building skills – especially their trainers and their biplanes. Their sport models are relatively simple but you’ll enjoy flying each and every one of them.

Purchase good quality tools – it does make a difference. Use sharp blades, good sandpaper (with a sanding block) etc.

Also use good quality hardware in your models. Many kits come with crap hardware that I generally throw away. Check out MicroMark for specialty tools and Micro Fasteners for good hardware.

Lastly, save everything! Whenever I come across materials that I think might be useful in my shop, I gather them up and put them aside. I am a pack-rat, but I also know when to throw things away. Usually if I have not found a use for something after a couple of years, I toss it.

Do you have <insert kit here> that you would like to sell or trade?

All the kits I currently have are listed here. If you do not see it listed then I do not have it.

Do you know where I can get plans for <insert aircraft here>?

Try contacting different modeling magazines (Flying Models, RCM, Model Airplane News, etc.). Also there are several plans services such as Bob Holman, Cleveland and others.

I have an airplane kit that I purchased about 6 year ago and was wondering if there is a, lets say "shelf life?" It is currently sitting in its box unbuilt on a flat surface and in a plastic bag. Is there a potential moisture problem from sitting to long, will the wood get warped or rotten? I try to keep it clean and dry as possible.

I live in an extremely humid environment (Florida) and have not had problems with kits that were stored for extended periods - some well over ten years. However I have noticed that old balsa tends to become harder and less flexible. I have not paid attention to whether or not the weight of the sheet changed, but it seems heavier as well. That may just be my imagination though.

The plastic bag may not be a good idea simply because it can trap moisture inside. If the kit is sealed then leave it that way. The best way to store a kit is in a climate controlled environment. I like to keep kits in the house until about a week before I begin construction. Then I move it into the shop so it can become acclimatized. Failure to do this increases the chances or parts warping during construction.

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