I am recovering a Kadet Senior with a specific scheme in mind. Since I don't want to get a lot of oil on it from a glow engine, I decided to use a RCG 15cc gas engine. I considered converting it to electric, but with my covering scheme, I want the gas engine noise. I was telling my plans to a friend and he was concerned about the vibration from a gas engine compared to a glow. He thought the airframe would vibrate apart. Has anyone used a gas engine on a Senior? Do I need to beef it up to handle the engine. The engine is heavier than a glow, but I will move the servo's to the tail and other balancing tricks to get it balanced out correctly.

Thanks

don't worry about the vibrations it will be ok. Isn't the senior is a 40 sized 2 stroke glow. a 15CC is like a 90 2 stroke glow. I'd be more worried about the power....
The wing loading isn't a factor as the airplane is a floater.

It's a bigun like the SR Telemaster. Vibration isn't any problem but the plane will fly with a good 46 glow engine so a 15cc gasser is really over kill. It will be clean running though.

I guess what I read on the internet is that the 15cc is the size of a 60 glow. That is stretching a Senior, but still tolerable. I won't run it full power. If you think it will handle the vibration, then I think I will try it.
Thanks for your responses.

This could be a mistake Depending on what Kadet Senior you are working with Exactly which one is it. Is it the Sig kit build version, the Sig ARF version, The nitro planes Super Senior or is it the World Senior Frontier?

John

G'day

I would not.

I have had about 7 or 8 Kadets Senior. I put a 90 four stroke in one which was the ARF Sig version. It was fun but I pulled it out after a couple of flights as I could see that if I persisted, I would pull it apart or worse, cause the wing to fail.

Remember, they were designed with a 29 to 35 size glow motor in mind. That is 5 to 6 cc. You are talking about three times that AND vastly more weight.

One of my current Kadets does have a 15cc engine in it but it is a three cylinder Saito 90R3 radial which is low in power and very smooth in operation. Each power pulse is that of a 5 cc engine not a 15cc one.

So NO would be my answer.

Mike in Oz

Several years ago, a duo in our club put a 90 two stroke on one. They played with it on the ground for a few hours, starting then stopping the engine for some odd reason, then asked me if I would mind "maiden'ing" it for them. I said, sure, why not, right?

So, I checked it out, basically making sure the servos were ok and connections were solid, then checked a few other things, asked about the CG, which they said was ok, having to add some weight to the tail to get it to balance out. For some resaon, I never picked it up. They carried to the runway. It was covered in all black, by the way. Odd color choice.

Aaaaanyway...

So, I put it up in the air. It took everything that 90 had to get it airborne, then would only keep flying if I kept the throttle darn near full all the time. I flew a few orbits, the thing flew like a tank with wings, then landed it.. somewhat hard because it flew so darned fast.

When I got it back on the ground, thankfully in one piece, I picked the thing up. It must have weighed about 10 pounds, possibly more. Very unusual for a Kadet. I asked them why it weighed so much, knowing it wasn't just the engine. Well, they put wrenches in the fuselage to try to get the thing to balance. When I say wrenches, I mean just that. One was a 5/8 - 3/4 " open end wrench.. you know, something you might work on your full-scale truck with.

That's my anecdote (true too) for today.

CGr.

You won't fly it at full power? so you'll either not push the throttle up so far, or will adjust the throttle not to go to full power.....then why in the world put a 15CC's weight in the airplane?
This is just way too much engine for that aircraft......and no a 15CC is not the same as a 60 2 stroke....the math says that it;s the same as a 90 2 stroke.
The other thing to consider is the 15CC will require a bigger prop. unless you put a longer strut on the nose or bigger tires you might not have the ground clearence.

.then why in the world put a 15CC's weight in the airplane?
Because I haven't seen a 10CC or 5 CC gasser? In my original post, I suggested that I am doing a special covering scheme and do not want to get a lot of exhaust oil on it. I would like the sound of an glow or gas engine over an electric.
I'm sure there are lots of ideas about directing the exhaust away from the plane, but there will still get to be some on it. I would like to keep it as clean as possible. Having said that, has anyone seen 5 or 10 cc gas engines?

With all due respect, you're essentially asking us the question, "What's the right way to do the wrong thing?"

That engine is too big for that plane. It's just that simple. If you want to minimize the oil mess go with a 4 stroke glow engine around .60 size. If the issue is that you're using a covering material that won't stand up to glow fuel, you just need to change your plans and do something fun with one of the film coverings or do a painted covering job with a glow fuel proof paint. I truly do understand the appeal of having gasser airplanes, but there is a practical minimum limit where they just stop working well.

Doesn't Fox sell a converted glow .50 size gasser? That would work. There is also a converted Magnum glow engine around. About .52 or so. Maybe Hobby People sells it. You run them off the receiver battery with an IBEC. So the only added weight is the ignition. Should be workable.

jollycub, you are facing a strong problem of less than adequate structural strength for such a weight up front. BTW, a .15cc is equal to a .90 glow engine. You can figure, for reasonable close, that 10cc is equal to .60 cubic ins. engine.

Let me give you an example: There have been numerous examples, in this area, of big gassers departing the airplane. Mostly on ARFs but a couple were machines designed for lesser power plants than the ones the owners bolted on the front ends.

One I witnessed: Modeler hangs a G-38 on an ARF designed for .60 to .90 glow. He thought it was the King of Kings. Well he made a rather hard landing, but all looked OK. Then he started it up again, and was taching the engine. Well that engine had a mind of its own and desided to fly without the airplane. Modeler learned to live without the thumb and first two fingers. THAT SIR IS WHERE YOU ARE HEADING! [:@]

I examined that firewall. I would not have put a .60 on it without significant additional structure on the fuse. ahead of the wing. Many ARFs are like that. I restructure maybe Overkill, but still have 2 thumbs and 8 fingers.

I have a Kadet Senior for initial training of newbies. It has some structural beefing-up in a few areas. It flies well on an OLD Bluehead ST. 40, 11-4 or 5 prop.

No matter your finish concerns, I strongly sugest that you redirect your thoughts about power application on your model. Painted finishes do well (1) use a good fuel-proff paint and/or a good fuel-proof overspray, and (2) if you clean them up well after a session. I have done and failed to have done such for some 65 years now. I well know the differences.

How about a Saito FB14B

Nobody will argue the idea of using a Saito FA-72 on a Kadet Senior - that's the power output of the FB14B and it (apparently) uses the Saito FA-82a crankcase.

What are ya waiting for? Gas is getting smaller every day.

9cc NGH gas engine, $179.00.<div>
</div><div>http://www.agaperacingandhobby.com/v...?productid=450</div>

Reading through this thread again, I have to agree with whats been said. There is no need to put a large gas engine on a Kadet Sr. If you want to run an engine that size, get an appropriate airframe like the AMR 20 which is designed for a gas engine. A Kadet Sr. is designed for slow flying, is best kept as light as possible with power kept low also. I've flown a Senior ARF with an RCV-56, and it was more than ample power. It would take off and climb easily at 1/2 throttle.

I've got a Senior kit that will be built stock - 3-channel and powered by a Magnum .52 RFS. I'll do some training with it, but mainly just enjoy putting around with it as was intended to be done. And the exhaust residue will be at a minimum with this engine.

Hogflyer

Thanks for everyone's responses. My primary reason for the gas engine is that it runs cleaner with an engine sound, not the power. What I had read was that the gas engine was the equivalent of a 60 glow. I am using Ultracote as a covering so it should stand up to glow residue, but I would really like to avoid that if possible. 600Bob, I am going to take a good look at your link. Depending on the weight, it's either that or electric. Have a safe Memorial Day everyone.

I have a DLE20 on my Deweyville, which is a rather large plane, very long, high wing, big wheels, tricycle gear.  When set with the tail and wing level on the main wheels the 16x8 prop clears the ground by about an inch or so.  When that engine idles the tail shakes quite a bit, but once it throttles up the tail stops shaking.  IIRC the fuse on the Senior is much shorter, so who knows how it would hold up to the idle vibrations of a gasser. Its pretty significant over a 4 stroke glow. <div>
</div><div>I'm looking to put a 3 blade prop on it because I feel the 16X8 will be too fast for the plane. </div>

jollycub- You have to be careful what you read, because not everyone who posts things on the internet actually knows what they are talking about. If you heard from someone who has actually used that engine on that plane and can give some real world feedback to you, then great. But there are way too many guys who know just a little bit about the hobby and will tell you that something will work when they really don't know if it will or not. There is a small grain of truth to the idea that this 15cc gasser is equivalent to a .60 glow engine. The peak horsepower is probably very close, since glow engines make more power for their size than gassers do. But the similarities end there. Your plane was designed to fly with a .60 glow engine, and many have flown them with less. An electric conversion is viable with some woodwork done, but to go gas requires having an airframe that is designed for the weight and the strong vibration of a gas engine. Stop worrying about the glow residue. Unless you are an extreme germophobe or OCD (in which case this isn't the hobby for you) the glow fuel slime simply isn't a big deal. You fly and then wipe the stuff off. It takes 2 minutes to get the plane clean and then it's back into the car with it.

This quote is from Oberst and a previous thread in the Beginners forum:




Voila.. no need for a gas engine on that Kadet.



CGr

Now that we're veering this thread off topic, I'll contribute my cleaning secret: microfiber polishing cloth from Pep Boys. I suppose a Wal Mart one would work too in a pinch. I can wipe a plane down with no cleaner at all and get the covering squeaky clean after a day of flying. I'll spray it after with the orange stuff to get the oil out of the seams, but that's it. I watch guys tear off one paper towel right after the other and smear that castor all around while I do one wipe and it's over. After about 20 uses the rag gets saturated so I hand wash it with Dawn and then toss it in the laundry with hot water.

Not off topic.. that quote is from the second sentence in the OP.

If you want to get technical, your post, Jester, belongs here.. http://www.rcuniverse.com/forum/m_11089553/tm.htm

BUT, I will overlook this transgression .. this time.. [X(]



CGr