Q40 Racer!
10-04-2010, 08:03 PM
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10-05-2010, 03:22 PM
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RE: Q40 Racer!
ORIGINAL: MJD
Doggone machinists never seem to want for custom engine mounts, do they..?
This looks like fun. Maybe we'll get a fast airplane session in before the snow flies.
Doggone machinists never seem to want for custom engine mounts, do they..?
This looks like fun. Maybe we'll get a fast airplane session in before the snow flies.
That would be awesome MJD.
Thanks for the compliments guys, sometimes I find myself wondering why I ever got into Toolmaking for a career, but sometimes it has its advantages.
10-05-2010, 04:55 PM
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RE: Q40 Racer!
Well glued with 30min epoxy and glassed in the 1/4" 5 ply firewall last night from behind and a bit around the edges in the front too, to tie it into the sides of the fuse, should be plenty strong enough.
10-23-2010, 07:29 AM
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RE: Q40 Racer!
Ok ready for some engine break-in/fiddling/tweaking today! AKA nerding out.
I'm using a APC CF 7.4x8 trimmed to 7", for starters.
I'm using a APC CF 7.4x8 trimmed to 7", for starters.
10-23-2010, 10:07 AM
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10-23-2010, 01:11 PM
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RE: Q40 Racer!
Well engine runs well once you get the rear rotor the right way[sm=red_smile.gif], it would only run backwards at first. Once I got that sorted out it ran awesome, have to shorten pipe more but peaked it after the third tank for a second at aprox. 22000rpm, but I got to tell you it goes thru 8ozs in a real hurry, not going to be much flight time on this airframe.
10-23-2010, 04:57 PM
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RE: Q40 Racer!
ORIGINAL: smoknrv4
Well engine runs well once you get the rear rotor the right way[sm=red_smile.gif], it would only run backwards at first. Once I got that sorted out it ran awesome, have to shorten pipe more but peaked it after the third tank for a second at aprox. 22000rpm, but I got to tell you it goes thru 8ozs in a real hurry, not going to be much flight time on this airframe.
Well engine runs well once you get the rear rotor the right way[sm=red_smile.gif], it would only run backwards at first. Once I got that sorted out it ran awesome, have to shorten pipe more but peaked it after the third tank for a second at aprox. 22000rpm, but I got to tell you it goes thru 8ozs in a real hurry, not going to be much flight time on this airframe.
Sounds like fun to me. Ought to haul around just fine.
10-30-2010, 10:35 AM
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RE: Q40 Racer!
Well today I ran 3 more 12oz tanks thru it, with 3 more 1/4" header trims, and no real change in RPM's,[sm=confused.gif],still holding peaked at 21 500k....w/ the prop mentioned before and 15% omega fuel, comments on this would be appreciated on this.
I also timed the runs on 12oz's I got about 7.5mins.
I also timed the runs on 12oz's I got about 7.5mins.
10-30-2010, 04:02 PM
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RE: Q40 Racer!
your header should be no more than two inches in length, once you shorten it your fuel consumption will go down, as it is over scavenging with the long header length, 22k rpm is prolly what it will do running open face.......
11-02-2010, 07:51 AM
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RE: Q40 Racer!
You might be over propped for your header tuning exercise as you want to hit in flight RPM - You are tuning for full song not ground RPM.
The .46 VXDF? purple head version with proper length header (and flying prop) will ground run 23,500 and unload to ???? in the air. Would think your engine would be capable of spinning as fast with the right prop.
The .46 VXDF? purple head version with proper length header (and flying prop) will ground run 23,500 and unload to ???? in the air. Would think your engine would be capable of spinning as fast with the right prop.
11-13-2010, 05:42 PM
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RE: Q40 Racer!
Well I did some more fiddling today outside with the engine and trimmed the header some more down to about 2 1/4" from the mounting flange to the pipe, and also did a series of trims on the 7.4x8 prop, its down to 6.4" in dia. now and I was consistantly hitting about 23300 rpm now.. ground peak.
11-13-2010, 08:38 PM
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RE: Q40 Racer!
Flight?
I have a lot more to do to the plane before I can fly it, just fooling with the engine for now. The cold weather is starting around here, I'll be mostly involved with indoor foamy flying now till the spring so this project will be on hold probably for now other than the odd muckin' about this winter, hope to have it ready for spring though.
I have a lot more to do to the plane before I can fly it, just fooling with the engine for now. The cold weather is starting around here, I'll be mostly involved with indoor foamy flying now till the spring so this project will be on hold probably for now other than the odd muckin' about this winter, hope to have it ready for spring though.
04-04-2011, 02:34 PM
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RE: Q40 Racer!
Well the warm weather is approaching, just have to wait for it to dry up at the field, its SOGGY[:-]! I've almost got this thing nipped, just a bit more fussin' with the cowl underneath, and its ready!
Goin with HS 225BB on the rudder, HS 475HB on the elevator, HS 81 for throttle, and HS 225BB on elevators. I think the most work was setting up the throttle linkage[:@], seems like a waste because it won't get used anyway, it'll be stuck on WOT. Also using an 8oz JETT bubbless tank on the CG.
Goin with HS 225BB on the rudder, HS 475HB on the elevator, HS 81 for throttle, and HS 225BB on elevators. I think the most work was setting up the throttle linkage[:@], seems like a waste because it won't get used anyway, it'll be stuck on WOT.
Also using an 8oz JETT bubbless tank on the CG.
04-04-2011, 03:19 PM
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RE: Q40 Racer!
Looks like a Cox 6-3 on the front.. I remember wondering if I was crazy firing up a piped .65 with a 7" dia bench prop. Just doesn't look right. Well, it didn't then.
Another white knuckle test flight for Southern Ontario this spring! I wanna watch, I wanna watch..
I remember wondering if I was crazy firing up a piped .65 with a 7" dia bench prop. Just doesn't look right. Well, it didn't then.Another white knuckle test flight for Southern Ontario this spring! I wanna watch, I wanna watch..
04-04-2011, 03:28 PM
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RE: Q40 Racer!
MJD, that's a APC 7.4x8 cut down to 6.4x8, that was the tuning prop I was using, for an actual flight prop I'll be using the full 7.4x8 or close to it.
04-04-2011, 03:49 PM
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RE: Q40 Racer!
Yeah, I knew it was the bench prop - it just looks doofy is all, like a 7" prop on a big block or the 5.1" prop I had on the OPS .15 for pipe set-up. Over the years of flying sport engines I guess your eyes get used to a certain relationship between engine size and prop size.
04-04-2011, 04:23 PM
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RE: Q40 Racer!
ORIGINAL: MJD
Yeah, I knew it was the bench prop - it just looks doofy is all, like a 7'' prop on a big block or the 5.1'' prop I had on the OPS .15 for pipe set-up. Over the years of flying sport engines I guess your eyes get used to a certain relationship between engine size and prop size.
Yeah, I knew it was the bench prop - it just looks doofy is all, like a 7'' prop on a big block or the 5.1'' prop I had on the OPS .15 for pipe set-up. Over the years of flying sport engines I guess your eyes get used to a certain relationship between engine size and prop size.
