Dynaflite Decathlon needs and engine
 

The sound says Honda GX25 4stroke but power to weight says something else.

But then again, that 4 stroke sound is so nice, and there is no oily exhaust, it is like flying giant scale electric without the battery problems and you get the sound.

Decisions.Any input?

RE: Dynaflite Decathlon needs and engine
 

Why not the Honda 31 or 35 then??

AV8TOR

RE: Dynaflite Decathlon needs and engine
 

I have a GX31 on the Rascal 110, a great engine, but just too large and heavy for that plane. The GX25 is lighter, smaller and not that much less power, but I am not sure it is powerful enough and not sure it is small enough. I need to get some exact specs and figures and maybe just go get one to see how it fits.

RE: Dynaflite Decathlon needs and engine
 

I have a US 41 engine in my Decathlon. It is rated at 3 hp and weighs about 4 and 1/2 pounds. It made the plane balance perfect and the spring starter spaces it forward just the right amount. I mix my fuel 32:1 and I get NO fuel residue anywhere on my plane. My Decath. weighs 18 pounds ready to fly. I build a little on the heavy side and it also has a scaled out interior and a full size pilot. I would not consider putting any smaller engine in my Decath, unless I wanted to just fly in large slow circles. The US 41 seems to be a perfect match for it. It uses a Top Flite 18X6-10 prop which gives plenty of ground clearance.

Bob

RE: Dynaflite Decathlon needs and engine
 

Bob: Was the Decathlon a easy build? Did you have to beef up anything much? Last...can you post a photo of it. Thanks Capt,n;)

RE: Dynaflite Decathlon needs and engine
 

That is the comprimise I am looking at I think, lazy floating with the GX25, why can't someone see the need for a 4stroke 40cc weedeater in the same size and weight package? I will post some pics later today. I can tell you the fuse is easy to build. I built the majority of it in one day just as a side project while working on two other planes. I suppose I am looking at a 30~35cc conversion 2 stroke.

RE: Dynaflite Decathlon needs and engine
 

Will try to snap those pics tonight, some more progress has been made. The only problem is that the main box is self aligning via tabs which would work great with flat ply. This ply is warped so making a straight fuse is a bit challenging. That said, I am not building this one as a showpiece, it will be a beater plane.

RE: Dynaflite Decathlon needs and engine
 

Captinjohn:
The Decathlon was an easy build and no, I did not feel the need to build it up in any areas. I did reinforce the landing gear as was suggested by another modeler. I used the cowl and wheel pants that came in the kit and assembled them using good old CA. I did not smooth the cowl...instead I just added a rivet effect along the seams. Looks great.I added tail braces which it really needs and the struts are functional because I think it needs them. The US 41 has some serious power and flys it perfectlly in my opinion. I'm considering building another one....to keep in reserve.
Bob

:D

RE: Dynaflite Decathlon needs and engine
 

I flew my decathlon with a poulan 42cc on CH ignition, power was great! and the balance worked out perfectly with the servos in the rear position. My plane weighed in at just over 14lbs with minimal detailing. I second the need to beef up the landing gear as illustrated above, great idea! I loved that plane but sold it when I got an offer I couldn't refuse.
http://www.members.shaw.ca/coolasacu...ineairborn.jpg

RE: Dynaflite Decathlon needs and engine
 

AirmanBob:

Are the wheel collars bolted to the gear from the top side?


Tym1_Me0

RE: Dynaflite Decathlon needs and engine
 

Guys: Will this plane do mild acrobatics. Loops, inverted flight, stall turns. and how about the snap roll or is that a no no with this plane. Thanks Capt,n:D

RE: Dynaflite Decathlon needs and engine
 

Funny, it just doesn't seem like it's big enough to be a gasser, next to the .40 sized ducted fan I am building it is only about 6 inches longer with the cowl on. So at first thought the 25cc seems like such a huge engine, but listening to people who have flown it, the 33 homelight seems like a good choice.

Here is mine as of today (this is about 1 days work spread over 2 days)

http://www.subarubrat.com/misc/dec2.jpg

RE: Dynaflite Decathlon needs and engine
 

Yes, the allen bolts go thru the alum gear and into the wheel collars just far enough to hit the 3/16 wire to keep it held in one place.

Bob

RE: Dynaflite Decathlon needs and engine
 

Subarubrat: Yep, that's the same Decathlon I built. IF you are careful, and build it really light, like 14 pounds, you could likely fly it with your 25cc. When you cover it be sure to use a covering that is light. I used Super Coverite (fabric) and that added quite a bit of weight. If I build another one, I will use monocote or something as light. I used large 1/4 scale futaba servos which are also heavy (but powerful). You could use some of the newer smaller servos that may be lighter and just as powerful. Just keep it light...

Bob:D

RE: Dynaflite Decathlon needs and engine
 

Treecutter,

Did you really need 42cc on your Decathalon, or was it a street rod? I've got a 1/4 scale Rearwin Speedster I'm thinking about putting either my 30cc leafblower motor or my 33cc chainsaw motor on. I just wanna fly around real scale-like with this thing. No upsidedown, knife edge, flatspin stuff. Great photo! Is that the velocity stack sticking out the side of the cowl?

Tym1_Me0

RE: Dynaflite Decathlon needs and engine
 

I guess it didn't need the 42 it was almost unlimited with that engine, but you can always throttle down, I think the 25cc would fly it very cub-like, ie less than scale I think the 33 would be perfect if you aren't into heavy aerobatics. This plane would knife edge, flew great invereted with a pretty high AOA rolls etc were no problem whatsoever and yes it would snap, although with snaps I used slow entry no full throttle stuff except for uplines.

RE: Dynaflite Decathlon needs and engine
 

Mine will do all those. Loops, outside as well as inside. Snap rolls are comparatively slower due to that big wing hanging out there. Nothing happens very fast, and that is part of the joy in flying this one. Knife edge? Yup, looks a little strange, but it does it!

RE: Dynaflite Decathlon needs and engine
 

I hit the home depot today and found the Homelite was on sale today for $80. The conversion parts are on order from Wacker motors.

http://www.subarubrat.com/misc/decath1.jpg

http://www.subarubrat.com/misc/decath2.jpg

RE: Dynaflite Decathlon needs and engine
 

So a Ryobi 31cc should pull it around with mild aerobatics?

RE: Dynaflite Decathlon needs and engine
 

Got the wings all covered and the servos in, this pic is halfway through but it is 100% done.

http://www.subarubrat.com/misc/dec3.jpg

Everything but the cowl and testflight is done.

http://www.subarubrat.com/misc/dec4.jpg