Power Systems for Extreme Flight Fanatics! - Page 249 - RC Groups
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Mar 09, 2013, 12:12 AM
bryansifsof44's Avatar
8500 RPM with a 22x10 is a bit more then 5.5HP, isn't it?
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Mar 09, 2013, 12:20 AM
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Aeroplayin's Avatar
I'll check, but that's what they are saying here, and I doubt they mean with a 22x10. Maybe they do.

Mar 09, 2013, 12:26 AM
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Crap, the pitch makes it a lot more that 5.5 HP. The 22x10 at 8500 is 9.1 HP with my calculations, and the ST calculator online says 10 HP. Something isn't right.

Mar 09, 2013, 12:30 AM
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Aeroplayin's Avatar
Maybe they meant 7500. That's what the DLE55 is saying... 5.5 HP at 7500 RPMs. That makes more sense. BHP at 7500 makes even more sense... 22x10 @ 7500 is 5.5 BHP, and that's the same as the 23x8, which is what everyone else I know is swinging on the DLE55.
Mar 09, 2013, 12:23 PM
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Here is the most reliable data I could find for the OS GT33 on engines that were broken in, which was tough. I'm not sure why guys post the RPMs all over the place without ever mentioning anything about the prop. I also found the same nonsense that drives us all nuts... "Try it, it's PLENTY OF POWER". Once again, weeding through the comments from guys that are just trying to qualify their own bad purchase, was painful.

One guy came on a OS thread and said... "just compare the price of replacement parts and I'll bet you will buy a DLE30 instead". Then a wink-wink, like these are some high level words of wisdom. Anyone who bought a DLE30, like me, knows all too well the cost of replacement parts because you have to start replacing them from day-one. After the cost of the ring replacement, the gasket set, and a tube of RTV, you could have saved yourself a lot of headaches, down time, and effort by buying a good engine in the first place. I was on the 91 thread and some guy was trying to convince another guy to put a DLE55 in the 91. "Plenty of power", he said. Really? Yeah, plenty of power for my grandmother, and she's dead. (And not that Dead is my grandmother )

18x8 APC to 8830 RPMs anf 20.2 lbs of thrust
My calculations show about 19.5 lbs to 22.2 lbs

20x6 Falcon to 7500 RPMs and 23.0 lbs of thrust
My calculations show about 21.4 and 24.3 lbs

20x10 APC to 6700 RPMs and 18.6 lbs of thrust
My calculations show between 17.2 and 19.5 lbs

The 22x10 on the A60 calculates to 25.84 to 29.36, which is about right, so I'm guessing the above three reports are very close.
Mar 09, 2013, 01:25 PM
bryansifsof44's Avatar
I posted some questions in a couple of threads for some rpm data on the bigger props for both the dle-35 and gt33.

LOL... 20x6 does a whoppin 43mph @ 7600rpm. Thrust is good though. HP and RPM seam to drop way down with just a bit more load. I was reading guys were getting the best performance with 19" props with these size of motors. Hopefully the DA would be the exception... 19" isn't what I am looking for.

EDIT: read bad things about the DLE-30, but not much bad literature on the DLE-35 and actually a lot of good has been said.
Mar 09, 2013, 10:39 PM
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I finally found the prop power calculator on my old hard drive. This was the Horsepower and Thrust calculator the guys at MVVS Engines in the Netherlands put together a while ago (a.k.a. Evolution Engines). They probably still have it as a resource on their Web site if you're interested. I ran the props that seem to be the most popular for the GT33 and the DLE35 and this is what I came up with. The calculations are at 28 ft ASL and at 68 degrees F.

Keep in mind that even the E-flite 1.60 with a 20x10 on 10S is producing 2895W, 3.88 HP and 23.3 Lbs of thrust at 7250 RPMs, according to this calculator. Additionally, the 22x10 on the A60 Hacker at 6850 is producing 4.79 HP and 28.8 Lbs. So regardless of where you are or what prop you are using, these values are all relative to each other because they are calculated using the same constants.

18x8 @ 8800
3.64 HP and 21.9 Lbs thrust

19x8 @ 7500
2.80 HP and 16.8 Lbs thrust

19x10 @ 7000
2.85 HO and 17.1 lbs thrust

20x6 @ 7600
2.68 HP and 16.1 lbs thrust

20x10 @ 6700
3.06 HP and 18.4 lbs thrust

The DA-35 will have to swing a 21x10 to 6850 RPMs to even come close to the E-flite power with 20x10, and it will have to swing that prop to 7280 RPMs to match the A60 on 10S with the 22x10.
Last edited by Aeroplayin; Mar 09, 2013 at 10:46 PM.
Mar 10, 2013, 05:10 AM
bryansifsof44's Avatar
This guy was getting blips in the the DA60 which he chocked up to the ignition. That was before he broke both elevator halves on landing.
Maiden Extreme Flight 91" Extra 300 EXP (13 min 5 sec)
Mar 10, 2013, 06:01 PM
bryansifsof44's Avatar
Mar 10, 2013, 08:01 PM
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Aeroplayin's Avatar
Originally Posted by bryansifsof44
This guy was getting blips in the the DA60 which he chocked up to the ignition. That was before he broke both elevator halves on landing.
Nice vertical. What prop is he using?

Edit... Oh, that's Canada... I thought you knew him.
Last edited by Aeroplayin; Mar 10, 2013 at 08:07 PM.
Mar 10, 2013, 08:14 PM
bryansifsof44's Avatar
I don't know... I just came across the vid.
You couldn't tell by the one guy.... eh!

On a serious note... what do you think was causing the hit... ignition? Sounds like the hits that gassers get at my flying site.
Mar 10, 2013, 10:48 PM
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Aeroplayin's Avatar
Actually, I know this guy. I've had a few engine conversations with him in the recent past. He knows his way around the 50, 55, and 60 engines and keeps some pretty impressive data. He's actually playing the EME 60 right now. This chart is from his test results with header lengths and props.


He's Bdeagan on FG, and I think he's Bdeagan68 on youtube.

I'm not sure why his ignition is blipping like that. Maybe not hot enough. We never ran less than 6.6V into the DA ignitions.
Last edited by Aeroplayin; Mar 10, 2013 at 11:15 PM.
Mar 10, 2013, 11:28 PM
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I count five videos I took of Tom flying Frank's 91 over the past three-day event at MCRC. We had 43 pilots the last time I saw the total on Saturday afternoon, and 145 cars of spectators, so probably 300 to 350 spectators. It's a nice local event. Today, the winds were 16 to 18 and gusts from 22 to 26. Not many guys were flying so Tom got seven solo flights and I loaded up the memory card. He flew the 91 now with the 24x10 Laminated Xoar, the 25x10 Beechwood Xoar, and the Vess 25A, which is an 8-pitch. The 25A is the prop that measured 41.7 Lbs on the digital fish scale, but was very noisy. Still waiting for the 24x10TH.

My friend Mark asked Tom to fly his old Pilot Yak-54 with a new smoke system. The only exciting thing about it was that he is now spinning a 23x9 Falcon carbon prop on the DLE55, which make a big difference compared to the 23x8 Xoar he had on there for the past two years. I had heard about this prop on the DLE55 before, but I finally saw it today. If I had a DLE55, I'd have a 23x9 CF Falcon too.
Mar 11, 2013, 12:09 AM
bryansifsof44's Avatar
How many RPMs on the 25A to get 41.7lbs of thrust?
Mar 11, 2013, 07:26 AM
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Aeroplayin's Avatar
The tach was mostly just over 6900. It did pop above 7000 a few times. It definitely was the highest reading so far and it was loud to the point of being painful while being close enough to take the reading on the concrete startup area. There were also signs of prop flexing on the 25x10 Beechwood. It may be time to put the 24x10 Laminated back on and take another reading too now that the engine has a few weeks on it. If the 24x10 can do 6800 now, and not flex as much, it may produce a lot more thrust.

I also asked Brad about the prop and about the ignition blipping, and he responded with... "The prop was a Vess 25A in that initial video. The engine misses were caused by the mini Thor IBEC. I took it out, put my regular optikill back in. Been fine since."
Last edited by Aeroplayin; Mar 11, 2013 at 09:48 AM.

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