Too fast for a c?

[Alan Fox]

Is this normal ? 24 square straight and level. Seems as fast as my fs and js have been..

[gwav8or]

I'd love to see that kind of speed from my F!  I typically see around 150mph IAS at 24 squared.  That's got to be a super modified C.

[hammdo]

25 sq no wind on my C - but I have speed mods:

[Alan Fox]

5 minutes ago, gwav8or said:

I'd love to see that kind of speed from my F!  I typically see around 150mph IAS at 24 squared.  That's got to be a super modified C.

Negative, just a power flo exhaust.... GPS backs up the speeds also

[Niko182]

maybe high compression cylinders that aren't logged?

[DXB]

Mine will 

51 minutes ago, Alan Fox said:

Negative, just a power flo exhaust.... GPS backs up the speeds also

My C is somewhat modded and has a Powerflow.   At 4000-7000ft, 10gph, it is a solid 150kt TAS machine at around 24 squared.  Under perfect conditions in the winter, it can push 155kt TAS at those altitudes and settings.  Your IAS is 150kt - assuming an OAT of 0C, that's about 162kt TAS - which would be insanely fast for a C.   

[Hank]

My Owners Manual shows at 5000 msl, 24/2400 is 80.6% power, and 165 mph True at 2200 lbs.

At that altitude, I generally run my C at22/2400 for 72% and 158 mph. Generally indicate in the low 150s mph.

No idea how you're indicating 170 mph, or 195 mph True . . . .

 

[Mobius708]

Have you worked backwards from groundspeed to find what the CAS/IAS should be?

Sent from my moto g stylus 5G (2022) using Tapatalk

[M20F]

44 minutes ago, Mobius708 said:

Have you worked backwards from groundspeed to find what the CAS/IAS should be?

Sent from my moto g stylus 5G (2022) using Tapatalk
 

This is the easiest way.  I see you have a GPS calculate TAS doing a 3 way and then compare with calculated TAS.  Will give you the answer in under ten minutes. 

[phxcobraz]

If you have OAT the 530 can also calculate TAS on the performance page. 
that’s certainly faster than my C by about 10kt+. It’s probably rigged very well and colder OAT. 

[exM20K]

and if the 3 leg test shows an airspeed indicator error, suspect alt static is open

-dan

[Rwsavory]

That's fast. Must be light and well-rigged.

[EricJ]

I've heard people claim getting that kind of true performance from a C before, but not indicated.    You're at the right altitude, though, and if it was reasonably cold out that might do that at true airspeed.    A light C with good aero and rigging can be pretty fast.

[Echo]

No.  It’s NOT normal. 

[bigmo]

My F doesn’t do that unless I’m pointed down! Well done!

Is it immaculate on the outside? Ive yet to buff and ceramic my F, but my last a/c gained more speed being super clean than any other $ I threw at it.

[201er]

Meanwhile Alan’s outside blowing the pitot 

[bonal]

Had to do a post annual flight today and thought it would be fun to see how it did at 24/24. Climbed leveled at 5500 and best I could do was 141 knots indicated which based on calculated trued at 154.  The air was moderately choppy and when I checked winds after landing they were 25knots 90 degrees cross at 5500 feet. Usually fly at 2400/20 I think might have been a bit faster if the air was smooth.  As for your example Alan, would like to see a couple pictures of that bad ass C to see if we can tell why it’s so bloody fast.  Now if you were to tell us that it was flying on G100UL for the first time it might make a couple of other threads on Moony space settle down a bit.

Edited January 13 by bonal

[hammdo]

I believe it is a late 1961 model (Dec 61?). A B with all the reductions to make it a C — and I believe 48 gallon capacity…

I can’t imagine the exhaust made that big of a difference something but sure did…

Damn fast for sure…

-Don

[0TreeLemur]

That doesn't make sense.  180 h.p. on our airframes can't make that happen.   I suspect the ASI.  Do a three leg and share the results then I'll start believing in miracles.  Flew my J to New Orleans today 24 sq. at 4000 ft burning 8.6 gph LOP, and was super pleased to see 142 knots indicated and calculated 150 knots TAS.   Your photo shows you were cruising at 5,500 indicating 150 knots, assuming your OAT was 5 C, your TAS was 160 knots!   Sorry.  I don't believe it.

[AJ88V]

Max book speed at 5000 MSL is 172 MPH (150 KTS) at 89% power (2700 RPM, 24.5 inches) burning 16.1 GPH.

1970 M20C is 140+ish knots at 10gph.  Mine has many mods but not smooth belly, 201 windshield, Powerflow exhaust, or hinge fairings which are the ones I'd like to have.  Said another way, the mods I do have brought her up to book speeds. 

The most-modded 'short body' is the CAFE Mooney (M20E)

http://cafe.foundation/blog/185-mph-on-6-7-gph-cafe-mooney-for-sale/

Pro-level interview of Kyle Kennedy by MS Member @Hair Helmet here: 

 

 

[gwav8or]

On 1/12/2025 at 11:09 AM, Alan Fox said:

Negative, just a power flo exhaust.... GPS backs up the speeds also

Well that is super awesome!  Wanna trade?  lol jk

[Alan Fox]

I just brought this one back from a runway excursion , So rigging of the gear , flaps , and ailerons were done , and I have travel boards , so they are rigged at Zero degrees , Not a super light aircraft , has 64 gal bladders... just stupid fast for what its supposed to do... I would throw a cowl closure on it , but what for ??

[takair]

Might be worth confirming no static leak into the airframe. That might push indicated airspeed up. I saw that recently on a different airframe.

[AJ88V]

1 hour ago, takair said:

Might be worth confirming no static leak into the airframe. That might push indicated airspeed up. I saw that recently on a different airframe.

Sounds like a really cheap mod for some extra speed!

(though it might interfere with your pitot-static cert)

[Echo]

So an unmodded C with a powerflow exhaust at 24 squared and 5500’ is doing 150knots?  That is the story being told?   Nope, but like scifi I love the tale

-Awww it's a crummy rigging commercial-Ralphie