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-   -   Engine Placement (https://www.rcuniverse.com/forum/arf-rtf-75/11048739-engine-placement.html)

Falcon32 04-19-2012 10:48 AM

Engine Placement
 
Hi Guys
I’m putting together a Seagull Edge 540 and will be using a DLE 20.
I want to use a wrap around Pitts muffler which is causing me a problem.
I can’t set the engine at the specified place because the can of the muffler is touching the front edge of the engine box. This means that the engine will have to be set about 3/16 of an inch below the correct place. I’m not too concerned if the cowl doesn’t look quite right, but I would appreciate your thoughts on what, if any effects this might have on how it will fly.

Thanks

Don

daveopam 04-19-2012 12:41 PM

RE: Engine Placement
 
I had a DLE 30 do the same thing on a 72" Yak. I just cut the engine box corner off at a 45 and epoxied in a piece of ply to replace it. The plane was made for glow so I also had to cut a whole in the front of the firewall for the carb to stick through also. I removed a lot of material, but so far no problems. It vibrates much less than the Saito 1.80 that was on there before anyway.

David

aussiesteve 04-19-2012 02:28 PM

RE: Engine Placement
 


ORIGINAL: daveopam

I just cut the engine box corner off at a 45 and epoxied in a piece of ply to replace it.

I also had to cut a whole in the front of the firewall for the carb to stick through also. David
Falcon32 - Those above are great advice - take note of them.

It is a simple task to take out a razor saw and remove a little of the engine box.

For the hole for the carb (If you need to cut one) a 2" - 2 1/2" holesaw is a good choice for just about any rear carbed gasser. If you use a 2 inc, you wil probably need to dremel a little to clear "corners"

Jetdesign 04-19-2012 02:37 PM

RE: Engine Placement
 
Don't change the thrust line.

Falcon32 04-20-2012 11:41 AM

RE: Engine Placement
 
Hi Guys
Thanks for the advice.
To be honest I'm not too keen on cutting the corner of the engine box.
It's probably easier for me to ditch the Pitts muffler and use the standard DLE one.
Anyone want to buy a Pitts muffler for a DLE 20 :eek:

Thanks

Don

Jetdesign 04-20-2012 12:15 PM

RE: Engine Placement
 
You shouldn't have a problem selling that in the classifieds, or in the classifieds on the group forum.

I think you made a good choice.

Cpt Crash 04-21-2012 07:59 AM

RE: Engine Placement
 
The other trick to try is to see how far forward you can move the cowl. If the cowl isn't predrilled or fixed by a cowl ring and there's enough fiberglass to make it work, you can slide your engine forward until you have proper clearances for the engine box, then move the cowl to the point where it aligns properly with the drive washer and/or spinner. My Phoenix Edge 540 worked out like this; I ended up sliding the cowl forward about 10 mm past where the specs were. There was plenty of material for the attachment screws, and it balanced out just fine.

Falcon32 04-21-2012 11:21 AM

RE: Engine Placement
 
I've just taken another look at it and by using the DLE muffler everything fits and I can move the engine up to the specified place with just a small mod to the cowl.

Thanks

Don

Falcon32 04-24-2012 10:52 AM

RE: Engine Placement
 
I’m still not convinced I’m doing the right thing with this.
If I give you some more detail you might understand my problem.
This plane was designed for a 90 size glow engine. The fire wall is pre drilled for a beam mount set at 270 degrees around to the right presumably to allow the muffler to exit out the bottom of the plane. The DLE is also a beam mount but I decided to use the more common inverted mount system for a gas engine.
So this is what I did:
I measured the fire wall and marked the horizontal and vertical centre lines.
The mount on the DLE is central to the prop driver so I placed the engine mount on the horizontal line but moved it over to the left to take account of the right thrust.
So from my point of view the engine is in the correct place, please correct me if I’m wrong.
Now the problem comes when I put the cowl on.
If I line up the cowl so that it’s sitting nice and square on the fuse and all the stripes line up etc it looks like the engine is too low. If I reposition the cowl so that it lines up with the spinner it looks a real mess.
So is my way to position the engine all wrong and do I raise the engine so that the cowl looks real nice, or do I put up with the cowl being ugly?
Sorry to take a second bite at this but I need your help.

I hope you guys can help
Thanks


mikegordon10 04-24-2012 12:11 PM

RE: Engine Placement
 
Guess I'd cut a corner off from the engine box and use the Pitts muffler. It really isn't hard to do and it's not a problem either. I'm not sure why you don't want to do this?

Falcon32 04-25-2012 10:47 AM

RE: Engine Placement
 
Well I'm not going to do it unless I have to.
If my method of positioning the engine is correct, then it's already in the right place.
The Pitts will fit where the engine already is.
It's only going to be a problem if my method is wrong and I have to move the engine up to get the thrust line correct.
So can anyone confirm that my method of measuring the fire wall is correct ??

Thanks

Jetdesign 04-25-2012 03:35 PM

RE: Engine Placement
 
Sounds like you didn't accommodate for any down thrust. It probably has a little.

Cpt Crash 04-25-2012 05:05 PM

RE: Engine Placement
 
When you look at the fuselage, is there any sign of right or down thrust already built into it, or is the firewall straight and level? Most of my planes had the proper amount of right and down engineered into the firewall, so the thrust line is correct and there's no need to tilt or move the engine. My old Phoenix Extra 330 Version 1 is the only plane that did not. Double check your firewall.

With the Phoenix/Seagull kits, it's also possible to use the original bolt holes drilled by the factory to find the centre point needed by the engine so it will line up with the cowl. Usually (but not always) this gives you a spot-on alignment and the cowl fits correctly. However, the paint doesn't always line up... My Phx E330 paint lines aren't even close, but she flies great.

Falcon32 04-26-2012 11:36 AM

RE: Engine Placement
 
Hi Guys
Looking at the old thread on this plane there's no side or down thrust built into the firewall.
Many people who have flown it say it doesn't like any down thrust but it does need the side thrust and I have accommodated for this by moving the engine over to the left and fitting a couple of washers on the left side of the mount.
Capt Crash I like your idea of using the original bolt holes to see where I'm at, I can probably use a paper template to do that.

Thanks

Don


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