RC TRAINER FROM SCRATCH
 

Hi guys
I am building my RC trainer out of scratch so my goal is to built a rc airplane that is under my budget I want to ask you that i have a gasoline engine from a small generator and its rated power is 2 hp and have 10000rpm and it weights about 4 kg so tell me that is it a suitable engine for a RC airplane which length about 6 feets and have a wing span of 1500 sq inch if any one of you have experience of that type of buliding so please relpy me any suggestion should be highly appriciated

waiting for your reply
falcon

RE: RC TRAINER FROM SCRATCH
 

I wouldnt touch this yall.

RE: RC TRAINER FROM SCRATCH
 

2 hp at 8.8 pounds is a very poor engine choice most of the 2 stroke gas engines we use like the quadra 35 and us engines 41 weigh about half about 4 1/2 pounds .is this a 4 stroke engine with oil in the crankcase?

RE: RC TRAINER FROM SCRATCH
 

yes this engine have oil in it

RE: RC TRAINER FROM SCRATCH
 

Great question! I'm not an aircraft designer so I don't know the correct answer, but I hope this thread brings in some people that know what they're talking about.

My feeling is that you're engine weighs too much.

Enlarging the plans for a typical trainer x 2 gives results that are more than twice your specifications of 6 foot length and 1500 sq inch wing, and yet your engine is nearly 9 pounds and the average trainer engine weighs about 1 pound.

For example, an LT-40 with an OS 46AX is an airplane with a 1 pound engine, a little over 1 HP, with a wing area of 900 sq inches, weighs about 6 pounds with a length of 56"

If you enlarged the LT-40 at twice the size with a 9 pound engine, maintaining CG would require many pounds of weight at the tail, and this is the issue. You'd go from what should be a 12 pound airplane at double the size to as much as 20 pounds due to beefing up the plans.

I think it would fly, but probably not very well. I think it would need to fly very fast to stay in the air, and I don't know if the typical trainer would be up to the task.

I assume this the only engine you have available, I hope you can make it work and hopefully someone will step in and say how pathetically wrong assessment is.

Can you strip the engine and make it lighter?

Once again, great question! I hope it works out for you.

RE: RC TRAINER FROM SCRATCH
 

It's probably legit, but who knows. RCU could nuke the thread if it's from a Proxy server.

RE: RC TRAINER FROM SCRATCH
 

your joking right?

your going to try to desighn a trainer around a 6 foot wing and an 8 lb engine and only put out 2 hp? My war bird weight 11 lb with a 6 foot wing and they are considered heavy, this is not even in the ball bark, it has a 1.5 lb engine putting out nearly 3 and though flies well need some runway.

Your best chance at a cheap engine is a small weed eater and even then the engine need t be highly mortified, lots of metal removal and balancing. I'm no saying it can't be done, just get a real trainer first , learn to fly then build a lead slead.

RE: RC TRAINER FROM SCRATCH
 

Hi
WestCoastFlyer
thanks for appreciating me i think that you are right that i strip the engine and make it lighter i will reply you when i overhaul the engine and get its exact power output and rpms and weight

RE: RC TRAINER FROM SCRATCH
 

Hi
redfox435cat
thanks for giving me right information and please tell me that what is awead eater engine and where can i get that one

must reply

RE: RC TRAINER FROM SCRATCH
 

Are you needed to start out with gas becuase glow fuel is not available or is it cost restraints. well I'm not sure what kind of stores you have in pakistan but here any department store or home and garden store would have a weed whacker, or a chain saw or gas powered blower or any other hand held gas powered equipment with a 2-stroke engine.

take this kit[link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDJB9&P=0]goldberge trainer[/link]

copy and add at least 30% to the size or every part, need a good bit of balsa and lite plywood.

then modify a gas engine so resemble these specs, or buy this

[link=http://www.horizonhobby.com/Products/Default.aspx?ProdID=ZENE26AEI]gas rc engine[/link]
these were designed for rc

RE: RC TRAINER FROM SCRATCH
 

you have chosen a bad engine for your project.do not even bother trying to strip it or make it lighter.with an airplane that is climbing and diving banking etc.the oil in the crankase will be sloshing all around and doubful it will keep lubricating the engine or even remain in the crankcse.sell off the generator/engine combo and buy a engine made for airplanes china makes a bunch either gas or glow

RE: RC TRAINER FROM SCRATCH
 

Weed Eater http://en.wikipedia.org/wiki/Weed_Eater
The term now is used to describe any brand of string trimmer used for landscape work.

Most have two stroke engines that use a mixture of gasoline and oil. They can run upright or inverted since they do not have a crankcase full of oil.

As redfox435cat suggested, if you can build a plane similar to any of these http://www3.omnimodels.com/cgi-bin/woi0093p?&C=AAB and install a 6.5 to 9 cc glow engine it will be much easier to get started.

RE: RC TRAINER FROM SCRATCH
 

The engine you're going to use isn't going to work under any circumstances.

Scratch building an airplane to try and save money will also not work under any circumstances. Even if you could build cheaper than you can buy (which you can't), you'll likely wind up with an unflyable airframe due to beginner errors.

Every beginner who wants to fly a fuel powered airplane needs to start at the same place: An ARF or RTF trainer with a .40 sized glow engine. The plane and radio and all the gear will set you back around $600 in the US once you allow for incidentals and memberships. There's no way to do it cheaper than that unless somebody gives you stuff.

RE: RC TRAINER FROM SCRATCH
 

I built the Sr. Telemaster as my club trainer with a used OS .60 and used Futaba standard servos with a used RX and the cheapest crap covering I could find. Total cost to get into the RC end of the hobby was under $250.00 even with the $12.00 club membership.
Three of us learned to fly with that plane before we gave it away. So much for the ARFs and RTFs. You can get into the hobby on the cheap.

RE: RC TRAINER FROM SCRATCH
 

You used used stuff and were lucky it worked. Good for you and your buddies. I haven't seen a club that only has $12 a year dues before, so I'll have to believe you on that one. You didn't mention AMA dues or any field gear either. If people at the field let a new guy use theirs then that's great but everyone really needs to have their own.

RE: RC TRAINER FROM SCRATCH
 

Hi
thanks for your nice suggestions and after all that i am changing my power unit and i think a gas engine from a wead eater would be better for that project so tomorrow i am going to find that one for me and i think it is better than the generator engine if any one of you have plans for a wead eater engine so please send them to me or any one want to give me any idea about that so please reply me

Abdul Samad

RE: RC TRAINER FROM SCRATCH
 

Plans are found in places like the Model Airplane News web site, the AMA web site or RC Modeler web site. Kit plans will do you no good at all because they do not show any of the ribs or former profiles for you to copy, you need builders plans.
The brush cutter engines also need to be modified for RC use, there are web sites for that too where you can buy some of the parts needed. There are places here on RCU also in the gas engine forum.
Are there any modelers or RC clubs in your area where you can get some help getting started?? You are going to run into a lot of problems just getting something off the ground and you may want to think about buying some used gear and equipment, maybe even a used plane that has everything already installed.
Just a thought.
Glow engines are a better place to start and I'm sure in your area or country people are blending there own glow fuel to keep the cost down, FAI fuel has no nitro, just alcohol and castor oil, it may be a better way to go.

RE: RC TRAINER FROM SCRATCH
 

Hi!
Just forget building you own trainer using a gas engine! First of all using an engine like this is dangerous! -Count your fingers! It is supposed to be ten...you will be lucky if you still have them around after beginning your model flying career with a big gas engine...

Why invent the wheel twice???
There are numerous ready-built high winged trainers out there that are well contructed and fly well..why build an plane that probably will not even will fly well...
I know! We want to learn on our own...doing our own thing! Right!? Yea! But build your own plane when you have learnt to fly! When you have learnt on something that really fly!

RE: RC TRAINER FROM SCRATCH
 

Here's my last post to this thread:

Trying to save money or effort by rigging up an airplane without having the experience to do it right is the same as throwing your money into the fire and burning it. Start with a .40 sized glow plane and get an instructor to help you and you'll do fine.

RE: RC TRAINER FROM SCRATCH
 

While Ive no advice for the OP, this kind of drivel is exactly why I almost didn't use this site, (no offense to the many wonderful folks here who DID help me along when I was starting out) . ARF or RTf.. $600 .. You go right ahead and throw money around like a rich man, I'm sticking with what I can afford, and BTW my RTF was $300, add $50 for starting gear and I was airborne. I now can build for around that or less, assuming I bought used gear.

Years ago, before the RTF and ARF days all a begginer had was scratch builds and kits, but strangely enough there are lots of old time flyers around that did it, some even on there own. So instead of telling this guy he simply can t do it give some real advice like the others here. Tell him his cjhosen engine wont work, fine, but tell him what will, Sheesh..

Falcon, try and get some good advice from here, and check out the SPAD Aircraft sub group if you are dead set on building from scratch, there's plenty of ways to build a good SAFE aircraft for about half the $600 he quoted or less..

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P.S.

I am by no means suggesting the OP's original engine choice, or idea was a good one. I certainly suggest getting help if you can Falcon, and NOT using that engine for the many reasons listed above.

RE: RC TRAINER FROM SCRATCH
 

Falcons Cuz,

I think if I was in Pakistan like you, I might consider a slope glider.

You need a location where there's a slope and some wind. The wind increases in velocity as it approaches the slope, and will carry the plane to altitude. You use the wind to gain altitude, then trade altitude for velocity, and fly back and forth. No engine necessary.

You can order the plane or kit & material from wherever you get your radio equipment. It's a good suggestion for a beginner. Another good suggestion would be for you to try a hotliner, a glider with an electric motor spinning a folding propeller, used to get the glider to altitude.

Either would be better than trying to use that 3.6 Kg engine.

Good luck,
Dave Olson

RE: RC TRAINER FROM SCRATCH
 

http://www.youtube.com/watch?v=6J7dG49VaGo&NR=1 Hope this helps .

RE: RC TRAINER FROM SCRATCH
 

What's the trampoline frame for?

RE: RC TRAINER FROM SCRATCH
 

Why thats the prop wash danger zone. . I thought every RC flyer had one. lolhttp://www.rcuniverse.com/forum/js/f...wink_smile.gif