Real-World Speed
- Andy Young
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Real-World Speed
I had to take my plane out and warm it up today to change the oil. It was dead calm, so I took the opportunity to do a speed run, to see how fast it is, set up how I fly it in the summer/fall (on big tires). I was just curious, but thought I’d write it up here in case the info is useful for someone.
The Plane:
M-6-235
VGs
31” Bushwheels
Baby Bushwheel tailwheel
Settings:
Full throttle
2400 rpm (redline)
Conditions:
No wind
30°f
Altitude 800’ MSL
Speed:
142 mph
In the past, I have found that I can get about 150 mph on 8.50s and a small tailwheel. Jeremy has, if I recall correctly, stated that a properly rigged 235 hp plane on 6.00s should go 154 mph.
The Plane:
M-6-235
VGs
31” Bushwheels
Baby Bushwheel tailwheel
Settings:
Full throttle
2400 rpm (redline)
Conditions:
No wind
30°f
Altitude 800’ MSL
Speed:
142 mph
In the past, I have found that I can get about 150 mph on 8.50s and a small tailwheel. Jeremy has, if I recall correctly, stated that a properly rigged 235 hp plane on 6.00s should go 154 mph.
- maules.com
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Re: Real-World Speed
The IO is slightly faster than the O540 (cowling shape perhaps)
On 7.00x6 TAS 155mph is what I recorded in the past. 29.92, 59F at sea level or extrapolated for altitude and temp change.
Unless in a hurry, I usually dawdle at about 21" 2100. A tad less speed, less fuel, but engine longevity and little chance of over leaning if not paying attention.
On 7.00x6 TAS 155mph is what I recorded in the past. 29.92, 59F at sea level or extrapolated for altitude and temp change.
Unless in a hurry, I usually dawdle at about 21" 2100. A tad less speed, less fuel, but engine longevity and little chance of over leaning if not paying attention.
- cubnak
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Re: Real-World Speed
Man, that is fast! I have an m-7 with the universal wing, IO540 and 86” McCauley prop, ext heavy duty gear and on 31”s with settings of 22” x 2150 rpm and I get around 115ish, when I swap over to 35” tires I drop 5-7 mph. I lost about 5 mph when I swapped from the standard gear that had the fairings and I know I can pick up a few mph by spending some time putting some fairings on in a couple places but it’s interesting that when I spool up to redline or beyond I really don’t gain much speed, maybe around 10 mph but I burn a ton more fuel. My best speeds for efficiency is when I go LOP and drop to about 105 mph on 35”s, 110 ish on 31@s and only burn about 9gph. Boy would I love to see your speeds but my plane just doesn’t seem to be able to get there no matter how hard I push it. But since I spend most of my time in a Cub I really feel like I’m getting somewhere at 105 mph!
My brother might chime in here but he owns Issac Bedingfields old Maule with the long wing, same gear, and on 35”s. When we flew together last summer he had 86” prop and I had 81” McCauley and I would pull away at same settings, he upgraded to MT prop and I put on his 86” prop and I would still walk away from him on 31”s, I put on 35”s this summer and we’re dead even at same power settings. Neither one of us have top speed like you guys are getting, pushing as hard as possible I might get 125 mph.
My brother might chime in here but he owns Issac Bedingfields old Maule with the long wing, same gear, and on 35”s. When we flew together last summer he had 86” prop and I had 81” McCauley and I would pull away at same settings, he upgraded to MT prop and I put on his 86” prop and I would still walk away from him on 31”s, I put on 35”s this summer and we’re dead even at same power settings. Neither one of us have top speed like you guys are getting, pushing as hard as possible I might get 125 mph.
- Andy Young
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Re: Real-World Speed
Yeah, I usually cruise at 22”/2200 rpm, going 120 mph. This as just a test to satisfy my curiosity, while also warming the oil up a bit faster.maules.com wrote: ↑Wed Oct 06, 2021 6:37 pmThe IO is slightly faster than the O540 (cowling shape perhaps)
On 7.00x6 TAS 155mph is what I recorded in the past. 29.92, 59F at sea level or extrapolated for altitude and temp change.
Unless in a hurry, I usually dawdle at about 21" 2100. A tad less speed, less fuel, but engine longevity and little chance of over leaning if not paying attention.
- cubnak
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Re: Real-World Speed
Andy, when you run full throttle and 2400 how much fuel do you burn and do you lean at all or just run full rich? Which engine do you have? Thanks for posting, interesting to see some real world results on big tires like most everyone up here is running.
- Andy Young
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Re: Real-World Speed
Well, I pretty much never do that. I just did it this one time as a test, for about five minutes. I left it full rich. I think it was reading about 20 gph, but I didn’t think to carefully check that.
I normally go just to 25” for takeoff (not full throttle, unless at an altitude that gives less than 25” at full throttle) then right after takeoff back it off to 22”/2200 rpm, and lean it to peak EGT. That gives me 12 gph. Even though that’s a “cruise” setting, it gives me more than enough performance for the climb as well.
It’s an IO-540-W1A5D. 235hp
- cubnak
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Re: Real-World Speed
Ah yeah, that makes better sense, same engine as I’ve got but your bird is definitely a bit faster. Hopefully we’ll see you out and about one of these days, if we all quit working think about all the fun we could have flying these things around! lol
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Re: Real-World Speed
M-5 235 HP with Goodyear 26" tires.
19" MP, 2400 RPM (sometimes 2300RPM)
120 KTS/138 MPH true.
I fly between 6000' and 11,000 MSL.
19" MP, 2400 RPM (sometimes 2300RPM)
120 KTS/138 MPH true.
I fly between 6000' and 11,000 MSL.
1980 M5-235
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- cubnak
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Re: Real-World Speed
Hey Andy, I was out playing around yesterday and had nearly calm conditions on the flight home so I decided to spool up to the same settings you had to get a comparison, full throttle and 2400 rpm I settled in at 130 mph with 31”s on. I had a little more rpm to give it but pretty much I’d say that’s my top speed in calm air. You have fairings on your gear right? I would like to do that and fairings on the strut forks just to see how much I’d pick up, I’m guessing close to 5mph.
Cheers, Ernie
Cheers, Ernie
- Andy Young
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Re: Real-World Speed
Hey Ernie,
Yeah, fairings on the extended gear, and tops of the wing struts. I haven’t made new ones yet for the bottoms of the wing struts; I put Airframes struts on the other week and the old ones no longer fit.
Yeah, fairings on the extended gear, and tops of the wing struts. I haven’t made new ones yet for the bottoms of the wing struts; I put Airframes struts on the other week and the old ones no longer fit.
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Re: Real-World Speed
Andy Y,
Ernie and I went out flying Yesterday. In formation, Ernie was 5mph faster than me with 31” Bushwheels. Sounds like I could get a few more mph with gear fairings.
My Plane:
1984 Long Wing, M-7-235, 235HP-IO-540-W1A5D
MT Prop
VGs
35” Bushwheels
Baby Bushwheel tailwheel
Fairings on top of Wingstruts, Extended Gear with no Fairings
Settings:
2200 rpm
22” MP
12gph
Conditions:
No wind
26 degrees f
Altitude 500’ MSL
Speed:
115mph
Rob
Ernie and I went out flying Yesterday. In formation, Ernie was 5mph faster than me with 31” Bushwheels. Sounds like I could get a few more mph with gear fairings.
My Plane:
1984 Long Wing, M-7-235, 235HP-IO-540-W1A5D
MT Prop
VGs
35” Bushwheels
Baby Bushwheel tailwheel
Fairings on top of Wingstruts, Extended Gear with no Fairings
Settings:
2200 rpm
22” MP
12gph
Conditions:
No wind
26 degrees f
Altitude 500’ MSL
Speed:
115mph
Rob
- Andy Young
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Re: Real-World Speed
You’re likely loosing a few knots to that long wing as well.
- Smokyray
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Re: Real-World Speed
Andy, I'm flying a bone stock M5-180 on 700:6's with the old BD Maule "speed spats" still mounted. I've kept it that way mainly for nostalgia and it's a great fuel stop conversation starter.(Brent commented over lunch at OSH that they add 1-3 mph each!) I can verify that on my M5.
Had a relatively cool, calm TX morning and I saw the following at 2500'
20"/2300 120 mph 105Knots GS
23/2400 128 mph 110 Knots GS
24/2400 133 mph 116 Knots
Coming back from OSH at 10.5:
19" WOT/2500 122KTAS
If I lived closer to AK or frequented soft ground I would slap on larger shoes but I get by just fine on 700's on turf, dirt roads etc.
Gotta like it...
V/R
Smokey
Had a relatively cool, calm TX morning and I saw the following at 2500'
20"/2300 120 mph 105Knots GS
23/2400 128 mph 110 Knots GS
24/2400 133 mph 116 Knots
Coming back from OSH at 10.5:
19" WOT/2500 122KTAS
If I lived closer to AK or frequented soft ground I would slap on larger shoes but I get by just fine on 700's on turf, dirt roads etc.
Gotta like it...
V/R
Smokey
- norcal64d
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Re: Real-World Speed
At 65% power with my MX-7-180 in calm air at 1500ft MSL and 60 degrees, 122 MPH IAS, about 125 MPH true. That is running 2300 RPM and right around 21.8" of MP.
Tim
1991 MX-7-180
1991 MX-7-180
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Re: Real-World Speed
When doing speed observations it is most accurate to calculate true airspeed based on altitude, temperature and barometric pressure. Indicated airspeed is not always accurate and varies according to installation. Ground speed, of course, depends on winds so not a true indication of speed either.
Most GPS's these days have a handy E6B type feature that make calculating TAS a breeze.
Most GPS's these days have a handy E6B type feature that make calculating TAS a breeze.
1980 M5-235
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