Continental 85hp on Avid Newbie help needed

[AvidRob 0]

Hello all, I am new here and new to Avid's. I have a Avid project that I would like to use the heavy haul wings, lengthen the fuselage, and use a C75 or C85 engine. I have been told there are some out there flying. Would anyone on here have one? Does anyone have any info and be willing to take the time to talk to me? Would like some info on what someone did on a engine mount? Any plans out there? Any jigs out there to borrow or buy?  I should also mention I have a Airdale cowling for a C85 / VW engine that is wider in the front for clearance. Sure it wouldn't perform like a 582 but I am not crazy about 2 strokes. Would think it still would perform good. Any help, info, 2 cents worth would be appreciated even if its negative. Thanks Rob

[EDMO 1078]

Welcome Rob,

Another 4-stroker here. The 85 should work in the stretch version - weighs less than my Soob with redrive. I modified my firewall to fit the mount from another plane that was with my soob. Don't see why you cant use a standard mount and do the same. Just try to get it as close to the firewall as possible. I ended up raising my firewall/cowl about 8 inches. My welder said the new firewall was strong enough to hang a Jake (radial) on.

ED in MO

I should clarify that I had also raised my seats and wings about 6 inches above standard, and extended the Leading Edge 4 inches. I have the short Kitfox type nose-dragger that I redesigned and scratch-built. Still trying to finish it.!!

Edited 12 Jun 2013 by Ed In Missouri

[Av8r3400 1178]

I have a friend who used to speak of an Avid IV with an O-200 on the nose. He said it performed very, very well, despite being heavy. I would think a C85 would do pretty well too. Keep the rest of the plane as light as possible and it should do well. A C75 would not be my first choice if a C85 was available. Remember the C75 is just a C65 with a few more rpm added, the C85 is a bigger stronger motor. Add an O-200 crank and you could have 115+ HP with little weight penalty.

[EDMO 1078]

I have been seeing the ads about 0-200 cranks for the 75/85 for years - figured that it did nothing but replace the old crank which is getting scarce - Care to tell me some more about it? What about the C-90?

EDMO

Edited 12 Jun 2013 by Ed In Missouri

[kosseman 3]

i have one of these it,s a c model extended speed wing with a c85 72" warpdrive prop.  

[dholly 718]

Ed-

Following info pulled from Harry Fenton's Hints and Tips for Small Continental Engines (a great resource BTW): http://www.bowersflybaby.com/tech/fenton.htm#rotax_replacement

Aircraft Specialties, 800-826-9252, has an STC for the O-200 crank conversion. Basically, this is your only option for a crank replacement if a C-85 crank can’t be located. All of the feedback I receive is that there is no downside to the O-200 crank (except the cost). If you are experimental, you can install any O-200 crank and O-200 pistons to approximate the STC without the paperwork. You can use the C-85 pistons, but you will need to machine a ¼†chamfer around the top of the piston crown for clearance in the top of the combustion chamber. The O-200 crank has a bit more throw than the C-85 and the C-85 pistons are a bit taller from the crown to the piston wrist pin. The C-85 pistons will give you about 5 more hp, but need to be chamfered for the clearance issue.

[1avidflyer 1983]

 

i have one of these it,s a c model extended speed wing with a c85 72" warpdrive prop.

 

Can you tell us more about it? Thanks, Jim Chuk

[AvidRob 0]

Yes, I would like more info about it also. Did you build your mount? Performance? Any cooling problems or anything like that? Do you have the long fuselage? If so did you still have to add any weight to the tail?  I have the speed wing and was going to buy heavy haul wings. Did you have your wing already built then add the wing extensions? I was told if you add the extensions to a already built wing that there is almost too much washout? I was going to sell my speed wings also if anyone out there would have any interest in buying them? Thanks Rob

[EDMO 1078]

i have one of these it,s a c model extended speed wing with a c85 72" warpdrive prop.

Here is one more vote to hear more about your bird, its performance, 2 or 3 blade prop, tires, floats, anything you want to write, and maybe a photo or 5 ?

EDMO

[EDMO 1078]

Ed-

Following info pulled from Harry Fenton's Hints and Tips for Small Continental Engines (a great resource BTW): http://www.bowersflybaby.com/tech/fenton.htm#rotax_replacement

Just guessing that a carb change would be needed, along with prop, and I don't see any 115 hp like someone said - unless you want a 10 hour TBO for racing...?

EDMO

[kosseman 3]

here's a couple of pics more details later in the day

 

[kosseman 3]

here's some numbers for you 

1,000 ft min

stall 48

empty weight 780

top level speed past vne 135 climb

 

This plane was totaled when i bought it. When i rebuilt it all the tubing from behind the strut carry thrue foward was replaced and upsized. The wings have and Eight foot spar insert in each spar. the tail was raised 10" and enlarged. the fuslage was not lengtened it will be on the next upgrade so i can move the battery foward and go to a new lituhum type. But i did sweep the wings foward 1 degree to help the cg. The plane flys great cruise is about 115 at 2350 burning about 5 gal and hour. Now the bad you have to be on ur game when you land it the speed wing profile landeds a little fast. When i get the time and money gonna build a set of kitfox 4 profile wings i think they will be just as fast and land slower. The lift struts were also increased in size.

[EDMO 1078]

WOW - Wish I could get even close to that performance with my 80 hp Subaru !!!!

One of our flyers with a 100 hp and IFA don't do that good.

EDMO

Edited 12 Jun 2013 by Ed In Missouri

[kosseman 3]

Well i have to admit it's not exatly a stock c85

 it could be closer to what was talked about a few post back

 

c85-8 case

c90 -0200 crank

c85 pistons

special cam

0300 cylinders

2 blade warp drive

balanced and ports flowed

and running premium auto fuel

[kosseman 3]

 numbers for when i had stock c85 with warp drive prop

 

600 to 700 ft climb rate

 

105 cruise

 

120 flat out

[EDMO 1078]

That is still some good numbers - Our undercamber wings are holding us back, IMO. I plan to modify my undercamber and hoping for better cruise.

Your engine sounds much like "I have a 283 Chevy", "Oh, forgot to say, its 400 hp!" Ha!

EDMO

[AvidRob 0]

Thanks for posting the info. Has been some deciding help. Could you give me any measurements like how far you have the engine out from the front of the fuselage mounting points? And some kind of measurement on where you have the thrust line. I see you boxed in the firewall for the mags trying to get the engine as far back as possible. I don't have a problem building a mount. Would just like a idea of where to set the engine for best location to get started. Thanks for your help. Rob

[kosseman 3]

Tomorrow after work I'll go to the farm and get some measurements? Planned on flying a little anyway.

[kosseman 3]

some measurements for you

top mount bolts down to crank center 7 inch's

firewall to prop flange 24"

every thing square with firewall no offset no down no sideways prop flange square with firewall

[AvidRob 0]

Thanks!  Rob

[SuberAvid 617]

Thanks so much for posting the information on this.  I think this is the first real good information I have seen on this install and what sounds like the excellent success you have had with it. How many hours do you have on it and were theremany bugs to work out?