Engine RPM Thread

WrongWay

Well-Known Member
Went back over a year... Dont thing there is an rpm thread on this site..

Any comparison data is good...

Any motor is good...

If you happen to have thrust data... that is great!



I'll go first.

Local temp 84.4. Humidity 74% Barometer 29.97 (smart phones are so cool) Wind -none...(protected area)

GP-61, on 4th tank of fuel.

Penzoil Aircooled 32-1 on 87 octane.

Prop, Falcon 24x9 carbon.

Exhaust GP 123 boxer type...(for a profile plane where I need the exhaust diverted)

6850 Hot on Rcexl Digital Tach

Load em up guys... we can use this as a go thread to for info... BTW, the spool up on this setup is very quick... Cant wait to fly it again.
 

closetguy

Well-Known Member
EME 60 6700 after first gal.Falcon 24-9,side dump,Wally World dino oil 32:1 on all readings.950 ft. ASL.
I think the EME is over prop with the 24-9.
NX 24-8 6700 - over prop
Xoar 23-8 laminate 6850 better great pull good speed
Vess 24a 7000 always trying to shift to next gear
Xoar 23-8 beechwood 7300 best spool up that's a no brainer,fastest speed in the bunch,rips a little,like this prop the best but not sure how long the engine will last.
 

Tired Old Man

Staff member
Unless that engine is turning over 10k it should last as long as you take care of it. I remember back to when Brison 3.2's (52cc) were used for wheeled drag racing. They didn't start to experience difficulties until turning over 13.5k.

Your flying style will establish if what you need is brute force grunt, steady increase to a sustainable high RPM, or quick RPM response with instant thrust response. As has been stated before, the highest RPM numbers may not be the best condition for what is the engine is being used for. Those were good numbers though.

Good thread. Let's see what others have to share.
 

WrongWay

Well-Known Member
I was getting 7400 on the JC 23x8 same day as post number one same engine/oil/temp. Spool up was very similar to the Falcon... But when I held the two props together the falcon has a footprint that is marginally smaller than the JC from say 25% to 75% away from the hub...

I was amazed to see the falcon 24x9 weighed in at 1.1 oz less than the JC.

The JC 23x8 was the white wood version that they don't make any more... Very stiff....

I flew the 23x8 on my 60cc profile last weekend... The GP61 pulled the plane around like a toy.... Plane is a concept profile model and was overbuilt... so just under 19 pounds fueled...88 inch ws.
 

Bunky f. knuckle

Cover shot, MA 10/09!!!
I'll play along with the rpm thread. I'm out flying with dad currently. Will have some rpm figures when he lands. He and I just put a new cam gear in his Saito 300 GK Twin last nite. He is on the 2nd flight with it. Sounds good!!!
 

Bunky f. knuckle

Cover shot, MA 10/09!!!
Saito 300 twin GK, Zinger 22x10 paint stirrer prop, 6462, rich on the ground.

3W 150 QS, Falcon 31x10W, 6080 cold.

Details on the day in Ohio.....

80F
29.99"
60%RH
65F dew point.
 

Tired Old Man

Staff member
Speaking of the old days and gasser drag racing, I wasn't aware they were still doing it. Engines are 90cc and even running nitrous now.

[ame]http://www.youtube.com/watch?v=FV3I65FiYWY[/ame]
 

WrongWay

Well-Known Member
Back from the field today... Temp 85, Humidity 71%, barometric pressure 29.93, same elevation (maybe 15 asl) Winds N-9 RPM read at due west (still forgot my white boots...:biggrin:)

Now at one gallon on the Falcon 24x9 7030 hot... The GP61 is a beast... Great throttle response... Still working on a slow tune to get rid of bottom end burble...Still doing circuits... next time out gonna start hucking it...
 

WrongWay

Well-Known Member
Disclaimer.. I dont sell this (GP) brand of engine... but wanted to try one and like it.:biggrin:
 

closetguy

Well-Known Member
Back from the field today... Temp 85, Humidity 71%, barometric pressure 29.93, same elevation (maybe 15 asl) Winds N-9 RPM read at due west (still forgot my white boots...:biggrin:)

Now at one gallon on the Falcon 24x9 7030 hot... The GP61 is a beast... Great throttle response... Still working on a slow tune to get rid of bottom end burble...Still doing circuits... next time out gonna start hucking it...



those are the best numbers I have seen for the GP on a side dump.
that's one strong engine looks like I will have to get one now.:banghead:
 

WrongWay

Well-Known Member
those are the best numbers I have seen for the GP on a side dump.
that's one strong engine looks like I will have to get one now.:banghead:
Its a boxer muffler. The exhaust goes straight out. A side dump the exhaust has to make a ninety degree turn... I dont know if there is any difference between the two... Still, a strong runner...
 

Attachments

WrongWay

Well-Known Member
Update.. I put the WW tuned pipe on it..

Rpm increase on the 24x9 was not that much... I may be able to trim a half inch off of the header... but torque... woah.. ponies...

GP-61, Falcon 24x9 Carbon, WW tuned pipe, 7120... It is most definitely unloading in the air but no data...Midrange torque went up... way up.. but again... no data...

19.5 pound profile plane is rag doll territory.
 

WrongWay

Well-Known Member
We also did some testing on props for DLE 20 at a recent event late Sept.


Quote below from CG post on pro bro site... The 17x6 carbon prop is a performer.

"First up was the Xoar 17x6. I have been flying this prop since the first flight on my DLE 20. It has good power on top end but has always been a little sluggish when pulling out. The next prop was the Xoar laminated and it seemeed to be just about the same as the regular Xoar I really couldn't tell any differenece between the two props. The laminated prop was much prettier though.....lol
The other props that I tried were Falcon props.The Falcon wood 17x6 had nearly the same performance of the Xoar props on the ground and in the air, however the Falcon carbon fiber props seem to be the cats meow for the DLE 20. I tried three of the carbon fiber props and each one had better performance than the next. The carbon fiber props were lighter and had a little less surface area than the wood props but seem to allow the engine to spool up faster and did not seem to lack in keeping air moving across the surfaces while the plane was stalled. The Falcon carbon fiber props that I tried were 17x7, 17x6.5 and 17x6 with the 17x6 being my favorite. It had the best performacne in the air and on the ground.

My engine was a little fat on the top end and I think I could have gotten a little more but the performance was fine for the test. My engine is a DLE 20 with a Bowman ring on a WW muffler for the profile so it points straight down and is on a 65" Mojo.
Here are the ground RPM's for the props:
Xoar 17x6 - 8580 RPM's
Xoar Laminated 17x6 - 8540 RPM's
Falcon (Wood) 17x6 - 8400 RPM's
Falcon (Carbon Fiber) 17x6 - 9060 RPM's
Falcon (Carbon Fiber) 17x6.5 - 8850 RPM's
Falcon (Carbon Fiber) 17x7 - 8640 RPM's"{
 

Rickster

Active Member
Almost a gallon through my GP61 with cowl muffler on a Mej 24x8 EVO. Still a touch rich but turns 7200rpm on the ground hot after landing.
 

anders e

Well-Known Member
My GP-61 on pf-pipe and mejzlik 24x10 = 7000+
The 123cc on pf-pipes and mejzlik 28x12 = 6580.
 

2robinhood

Member
Not sure of actual weather conditions, but it was 90 degrees and humid.
I also am at sea level.

DLE-55 on it's fifth tank of fuel.
Stihl Ultra HP @ 50:1
Stock muffler
Bowmen ring
Reed block mod
Falcon carbon 23 X 9
7150 rpm top end

.

DA-170
Stihl Ultra HP @ 50:1
RE3 pipes on 14" headers
Vess Stealth Carbon 32C
6450 rpm

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DA-170
Stihl Ultra HP @ 50:1
RE3 pipes on 14" headers
Falcon carbon 31 X 10W ( wide )
6550 rpm

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