I am getting ready to start a new project. One of the 90 inch Revolvers. I am wanting in to be a fast plane. I am not looking for an acrobatic or 3D bird. I have those and this is solely for speed. However, I want to stay within the parameters the plane was designed for. I was wondering which engine between the DLE61, DLE55, and the DA50 which would generate the most speed on level flight? The reason I am using these 3 engines is price. I am trying to keep the engine cost in the $350 range. I know the DA is going to exceed that but I have one on another plane and could use it in a pinch and upgrade it.

Like I used to tell my wife bigger is not always better but then she is now an ex wife. Lol

Thanks

If your looking for just speed get the dle61 with an APC 20x15 T6 prop.

Between the three engines you listed, I doubt you will find huge differences in speed. All good engines, these reed valve engines put out their best power in the mid RPM range and are best suited to aerobatic use. If you are wanting to go fast, I'd recommend one of the older piston ported engines like a Zenoah G-62, Brison 3.2, Taurus 53, BME 58 Extreme, FOX 3.2, etc. Any of these or similar engines are ported to run in the upper RPM ranges and will provide the speed you are looking for. Some are still available new but most will be found on the used market. Try props in the 20 -21" diameter and 10+ pitch range and you will be pleased. APC makes a special racing prop for the G-62 if you're really feeling crazy.

Now if you're looking for a speedy, not necessarily fast plane, go with any of the engines you mentioned. The 61 will pull a bit more prop load just because of its size though I think the 55 is ported for power at a bit higher RPM range.

Originally Posted by jaync

If your looking for just speed get the dle61 with an APC 20x15 T6 prop.

I like my DLE 61 but I don't know if it would hold together over the long haul turning 10,000 RPM ..... if it could even turn that prop that fast.

My friend has a DLE61 with that APC 20x15 T6 race prop on a TF giant P51 and its wide open from wheels up to the last lap lol. It holds together and its really fast. Only issue with that prop is it doesnt have much low end thrust since its built for racing. Have to be careful on take offs and landings

I just get nervous with any cantilever crank turning those RPMs.

I hear you there, so far I havent seen one let go.

Sounds like a fun project! I think the DLE-61 with the usual reed block blueprinting and Bowman ring, plus a pipe would give you another ~500 RPM.

I'm putting the same engine in my TF giant zero with the bowman. I will put the T6 prop on it after a few gallons.

I wish this was happening closer to my part of the country. I'd be putting my money on one of those older engines! Its hard to beat an old chainsaw cylinder when you get up in the RPM ranges.

I have the DLE-61 in my TF zero has awesome speed and unlimited vertical climb. I'm very happy with this motor.

Thanks guys. Sounds like I need to get my 61 on backorder and have it shipped to Mr. Frank Bowman for his mods. I wish I hadn't sold my Taurus engine from a few years back. Didn't know what I had at the time.

I'm getting a couple T6 props myself. One for a G62 and giant razorback, and one for a DLE 55 powered 80" zero. Should be fun!

The 55 will turn the T6 but it doesn't wind up like the 61. Might be ok on an 80" plane though.