The speed thing...How fast REALLY is plane...

[scottfromiowa]

Quote: jetdriven

We can get 8.0 GPH st 2500 RPM at 7500' but it is quite lean at that setting, maybe 50-75 LOP.  We use more like 8.5-8.7 GPH. Are you at WOT?  The air distribution is more even there.  Try soaking your injectors in Hoppes #9 or acetone overnight and clean them up.  What is your GAMI spread?

[jetdriven]

FWIW it takes 45 minutes to remove the injectors and another 45 to reinstall. 

[scottfromiowa]

Thanks.

[FlyDave]

I have a 1982 201. 7,500' - 8,500', 2500 RPM, WOT, whatever MP I get, I get 157 KTAS on 10.7 GPH.

[201er]

Flew a 2 hour flight to Niagra falls and back today. At 6,500' MSL (guessing 7,500 DA) at WOT, 2500RPM, 25ROP, ~23" MP, I was managing a true airspeed of approximately 155ktas but only 140 on the gps. Fuel flow was 11gph on the instrument (not calibrated) and 10gph on the dipstick (not particularly accurate). From the POH, I would interpolate this to be about 68-72% power. So not quite 75% but over 65.

Coming back was 5,500' MSL (guessing 6,500' DA) at WOT, 2500RPM, 25ROP, ~24" MP, I was managing a true airspeed of about 152ktas and 152-158 on the gps (bit of a quartering tailwind). 10.9GPH on the fuel flow.

This is all in a stock '78 201. I gotta figure out how to squeeze a few more knots out of it. Not sure how the rigging is but it looks like there are gap seals in all the control surfaces. Any tips?

[Parker_Woodruff]

Quote: scottfromiowa

Thanks Parker and Mike.  Parker did you fly mostly at 10GPH with the nice increase in speed?

[bnicolette]

Here is a TAS test I did a couple months back in my '82 M20J; sorry, no fuel flow information:  My airplane also needs rigged as the ball is slightly out of it's cage in cruise flight to the right about a 1/4 ball.  An upcoming visit to Henry Webers hopefull will fix that issue.

 

 

Altitude	OAT (F)	MP	RPM	Direction	IAS (KTS)	GPS (KTS)
7500	28	22.4	2400	S	157	166
7500	28	22.4	2400	E	157	169
7500	28	22.4	2400	N	157	143
7500	28	22.4	2400	W	155	140
					Average G/S	154.5

 

 

 

[Shadrach]

Quote: scottfromiowa

 What is your fuel flow at this setting Ross?

[scottfromiowa]

Thanks Ross & Brett.  That is great speed at 2400RPM!

[jelswick]

Sounds like my J (or it's pilot) is a heavy drinker of 100LL compared to others on here.  I typically see 155-160 KTAS depending on weight at about 11.5 GPH running 25 squared, 75-100 ROP and cowl flaps closed.  Typical altitude for short hops around Ohio or neighboring states is 5,000-8,000 MSL for me, higher altitudes and better fuel burns if going somewhere like the beach. 

[scottfromiowa]

The rub for me is I have ALWAYS flown LOP.  When I enrichened at 7500 feet to 11GPH I saw a SIGNIFICANT INCREASE in Cylinder temps and Oil Temp.  Higher than I had ever seen before...I DIDN'T see any signifigant increase in speed with the indicated 11GPH or 11.5GPH over the 10GPH LOP setting...Love you J's and Rob's C speed at the fuel flow.  I am still happy with my 145knot E at 10GPH.

[DaV8or]

Scott-

If you want J speeds and efficiency, you need J aerodynamics. The two biggest are winshield and cowling. I guess you have the windshield, but IMO the cowling is just as important. Sadly, your options these days are kind of crappy. You can try for a genuine 201 cowling with a field approval (not likely in the new FAA climate) or the LoPre$ti cowling. Unfortunately, the nice compromise, the SWTA 201 "style" cowling is no longer available.

I feel the days of mods are coming to a close and if we want to go faster, we have to do what many on this board seem to be doing and that is, change airplanes.

[Txbyker]

I have a 1987 M20J Lean Machine.  The Lean Machine has the squared windows, no wing step, less interior weight, and less factory instruments.  When launched they only had one radio and no autopilot although since then mine has been upgraded to the normal assortment of gadgets with comparable weight.  At 8000, WOT, 2500 RPM, 50 degress ROP I consistantly see 163 KTAS and about 11.2 GPH.

 

[scottfromiowa]

Hi Dave:

I'm O.K. with my speed.  I just find it interesting to hear speeds of other Pre-J airframes and learn a little more about how others fly their planes in cruise.  I have the lower cowl closure and the overlapping gear doors and the smooth one piece belly.  The three blade is probably a few knots (in cruise), old paint and lack of rudder/aileron fairings as well as the more efficent J cowl with further modified opening and oil cooler re-location.  For my flights 130-155 knots (depending on winds) is fine.  We are talking 15 minutes (longer) at the trips I take so no worries.  I like the climb performance of my prop and don't have the vibration issues that others discuss.  I love my plane.

[scottfromiowa]

Hi Russ.  Nice plane.  There are a LOT of articles that discuss this.  Please (everyone) DON'T turn this into a ROP/LOP RED BOX thread...

[rbridges]

Quote: DaV8or

Scott-

If you want J speeds and efficiency, you need J aerodynamics. The two biggest are winshield and cowling. I guess you have the windshield, but IMO the cowling is just as important. Sadly, your options these days are kind of crappy. You can try for a genuine 201 cowling with a field approval (not likely in the new FAA climate) or the LoPre$ti cowling. Unfortunately, the nice compromise, the SWTA 201 "style" cowling is no longer available.

I feel the days of mods are coming to a close and if we want to go faster, we have to do what many on this board seem to be doing and that is, change airplanes.

[Guest]

Owned my mooney for the past 16 years. I get 152 kt with basic airframe upgrades. No 201 windshield upgrade I like the avionics access. Full throttle for cruise at 6k-7k 2500 rpm. Pull mixture till it runs rough and richen till it smooths out.  I average 10.1 gal hr. 

[Shadrach]

Hey Scott, I would definately have a looky at your injectors/intake. If I were to lean untill rough and enrichen until smooth, that would put me anywhere between 90 and 30 LOP depending on RPM and MP. I've stock injectors and have never messed with their position. I think the possiblity of an intake leak more likely than injector goo...

[Shadrach]

Quote: BluSky

Owned my mooney for the past 16 years. I get 152 kt with basic airframe upgrades. No 201 windshield upgrade I like the avionics access. Full throttle for cruise at 6k-7k 2500 rpm. Pull mixture till it runs rough and richen till it smooths out.  I average 10.1 gal hr. 

[dcrogers11]

The last speed check in my 64C.  2400/22 MP and not pushing it too hard.....

[Guest]

A true Mooniac should know what model it is just by looking at the pictures . HE HE

Its a 70 C  / Millenium Engine / Power Flow etc.

[Guest]

dcrogers,

THATS THE BEST !!!!!!!!

[Ned Gravel]

Quote: BluSky

dcrogers,

THATS THE BEST !!!!!!!!

[scottfromiowa]

Quote: BluSky

Owned my mooney for the past 16 years. I get 152 kt with basic airframe upgrades. No 201 windshield upgrade I like the avionics access. Full throttle for cruise at 6k-7k 2500 rpm. Pull mixture till it runs rough and richen till it smooths out.  I average 10.1 gal hr. 

[scottfromiowa]

Flight aware has only one listing.  135 knots.  Slow day.