Improved speed documented

[David Lloyd]

Years ago I had a 1965 C.  When I bought it, I remember seeing 140-143 knots depending on loading, altitude, temp, etc.  In the quest for more speed I had gap seals, landing light cover, aileron seals, empennage hinge seals, empennage fairing, dorsal fairing wheel well enclosure, and brake rotation.  When I sold it, I could count on...yep, 140-144 knots depending on loading, altitude, temp, etc.  Quite a bit less improvement than promised before the checks were written.  At the time, I don't remember anyone installing the 201 windshield or cowling.  Maybe, maybe not.   I did however, attempt to make a fiberglass cover to block off that big hole in front of the engine cowl.  Gave up--hate fiberglass.  I discussed that with someone at a fly-in.  Hmm.

In another thread, someone asked about the speed of the F model.  Comments have speeds all over the place.  Same for the E and C. Looking at Flight Aware it would appear 140 knots for the C and F and 145 knots for the E are pretty common.  About the only mods where there seems to be a true benefit are the 201 windshield and cowling.  I have searched but have been unable to find where anyone documented before and after testing when modifications are done.  Seems faster, definitely is faster, a lot faster is not a test result.  Anybody do any real before and after testing?  

Other vintage Mooney mods in addition to what was already mentioned are: LoPresti cowling, closure, 10:1 pistons, IO-390, Power Flow exhaust, flap and aileron hinge covers.  Anyone have some hard info?

 

Edited August 15, 2018 by David Lloyd

[Mooney-Mark]

I have a 68 M20C with a bunch of mods (inc. 201.windshield) and get 140-143kts, WOT and 2500 RPM AT 7-8,000 ft.  Still searching  the illusive 150 kts.

[NJMac]

Im going to have to agree.  145kts ground speed seems about right for my E.  I had read its a 155kt plane.  Who knows.  When I do the calculations on TAS after the fact from memory, they come in higher but it could just be my memory failing me on a baro being off or something. 

[David Lloyd]

Fuel flow does have a big effect on TAS.  My RV with everything just right will do 177 knots TAS but the flow is about 11.5 gph.  Dial the rpm back to 2500 and flow about 9.5 will get me 170 knots. Bring the flow back to LOP, about 8.5 and 162 knots.  7.5 GPH, 155 knots. Yep, 4GPH will make a 20 knot difference.  Blue, was there any speed difference at the same fuel flow?

[MyNameIsNobody]

Jeez Jim.  Buy a fuel flow monitor.  Used they just aren’t that expensive.  Otherwise you are just like the F Thread guys that refuse to give fuel flow when talking (I won’t say bragging) about how fast their planes are.  I will comment that Lloyd did the same thing when discussing his Mooney...Then he is all about the speed difference at different fuel flows in the RV.  Ground speed is massively impacted by wind and fuel flow.  NOT MODS.  You are talking about a massive difference in speed if you flow 11.5GPH vs. 10.  That said you are likely talking about a difference of 10 minutes an hour for arrival time.  Just not a big deal.  Guys that heavily mod Mooney’s are crazy, but hey it is their money.  David’s cowl doesn’t seem to make that much more speed so it comes down to aesthetics...Worth $3500+ for a modern look?  Is to some.  (But NOT if my oil and cylinder temps go up a lot)  To me I just burn an extra gallon an hour or $5 bucks if I want to “go fast”.  Usually 130-160 knots ground speed up at 5500-7500’ depending on winds is what I see.  I am good with that.  I wish people would report ground speed vs. instruments because I don’t trust those numbers either.

[MyNameIsNobody]

And two posters here don’t give fuel flow either.  Face palm...

[MyNameIsNobody]

You know what will be awesome?  If a turbo guy talks about how fast his plane is...Or a Huge engine on a Comanche, or an experimental. Good times.

[N201MKTurbo]

Once I was flying right seat in my friends Citation. We were flying from Mesa Gateway to Palomar CA. 

We watched a Mooney taxi out and take off. 

We farted around for a while and finally got around to firing up the jet. We taxied out and flew to Carlsbad.

We landed and parked the jet.

We looked out and saw the same Mooney land.

 

The moral of the story is; you don't need a faster plane, you just need to stop farting around the airport.

[Sabremech]

1 hour ago, MyNameIsNobody said:

Jeez Jim.  Buy a fuel flow monitor.  Used they just aren’t that expensive.  Otherwise you are just like the F Thread guys that refuse to give fuel flow when talking (I won’t say bragging) about how fast their planes are.  I will comment that Lloyd did the same thing when discussing his Mooney...Then he is all about the speed difference at different fuel flows in the RV.  Ground speed is massively impacted by wind and fuel flow.  NOT MODS.  You are talking about a massive difference in speed if you flow 11.5GPH vs. 10.  That said you are likely talking about a difference of 10 minutes an hour for arrival time.  Just not a big deal.  Guys that heavily mod Mooney’s are crazy, but hey it is their money.  David’s cowl doesn’t seem to make that much more speed so it comes down to aesthetics...Worth $3500+ for a modern look?  Is to some.  (But NOT if my oil and cylinder temps go up a lot)  To me I just burn an extra gallon an hour or $5 bucks if I want to “go fast”.  Usually 130-160 knots ground speed up at 5500-7500’ depending on winds is what I see.  I am good with that.  I wish people would report ground speed vs. instruments because I don’t trust those numbers either.

If you're talking about my cowling mod, Matt and I both gained 5kts. We have the data to prove that. Bob and Wayne's, not so much. I don't know why other than every Mooney is different, with different performance when you'd think the same models would be close. No so. The oil temp issue is not a result of my cowling mod. That was going on before my mod and doesn't seem to have gotten worse because of it. Cylinder temp also isn't a problem on one and we just about have it handled on Matt's. Again, makes no sense why two airplanes that have the same engine are quite different with the mod. 

Call it what you want, $3500+ for a modern look, for me and quite a few others, Yes. If not for you, then move along and don't bash something you really don't know all the details on ( oil and cylinder temps go up a lot). 

Thanks,

David

[mike_elliott]

1 hour ago, bluehighwayflyer said:

Hi, David. Our C isn’t equipped with a fuel flow instrument, so the best we can do is fly known flight profiles and then compare total fuel added.  So a guesstimate at best and why I can only report the C’s cruise fuel burns in generalities.  There is definitely an increase in both fuel burn and performance, though, as a result of the PowerFlow exhaust and new engine combination.

I can report that I can fly the J LOP at 8 to 8.5 GPH in formation along side the C flown ROP at max power or slightly richer, probably at around 10.5 GPH.  All at around 145 KTAS.  That is a pretty remarkable evolutionary increase in overall efficiency for the J, I think. 

I am very envious of your RV’s numbers.  

Jim

 

Ok, time to brag for Joe Dion's J... Here are the numbers and the proof...

[MyNameIsNobody]

16 minutes ago, Sabremech said:

If you're talking about my cowling mod, Matt and I both gained 5kts. We have the data to prove that. Bob and Wayne's, not so much. I don't know why other than every Mooney is different, with different performance when you'd think the same models would be close. No so. The oil temp issue is not a result of my cowling mod. That was going on before my mod and doesn't seem to have gotten worse because of it. Cylinder temp also isn't a problem on one and we just about have it handled on Matt's. Again, makes no sense why two airplanes that have the same engine are quite different with the mod. 

Call it what you want, $3500+ for a modern look, for me and quite a few others, Yes. If not for you, then move along and don't bash something you really don't know all the details on ( oil and cylinder temps go up a lot). 

Thanks,

David

Counterpoint.  One mans bashing is another’s questioning...I’ll move on when I feel like it.

[MyNameIsNobody]

13 minutes ago, mike_elliott said:

Ok, time to brag for Joe Dion's J... Here are the numbers and the proof...

What is the fuel flow.  I can’t read it.

[Sabremech]

10 minutes ago, MyNameIsNobody said:

Counterpoint.  One mans bashing is another’s questioning...I’ll move on when I feel like it.

I didn't see any questions in your post. I'm moving on! 

[AH-1 Cobra Pilot]

2 hours ago, David Lloyd said:

My RV with everything just right will do 177 knots TAS but the flow is about 11.5 gph.  Dial the rpm back to 2500 and flow about 9.5 will get me 170 knots. Bring the flow back to LOP, about 8.5 and 162 knots.  7.5 GPH, 155 knots.

Those numbers are pretty close to theory:

KTAS              GPH                  Predicted % Increase     Predicted KTAS
155                  7.5                                    -                                   -
162                  8.5                                 4.3                                161.6
170                  9.5                                 8.2                                167.7
177                 11.5                              15.3                                178.7

It is always nice to see theory and experiment coincide. 

 

Edited August 16, 2018 by Ah-1 Cobra Pilot

[mike_elliott]

21 minutes ago, MyNameIsNobody said:

What is the fuel flow.  I can’t read it.

8.5

12 minutes ago, bluehighwayflyer said:

Hi, Mike. Yeah, you’ve posted that before. That is one crazy fast and efficient J model!

Jim

Yea, it is a beast. Now that Joe had it painted, it’s pretty also. Funny thing is it could be faster, the ball is slightly off center. One of the ailerons is tweaked some per dmax

[jetdriven]

Just remember the Aspen calculates true airspeed from the IAS which if you look in the POH reads about 2 to 3kt  high at cruise. CAS is less. 

[Andy95W]

56 minutes ago, Sabremech said:

If you're talking about my cowling mod, Matt and I both gained 5kts. We have the data to prove that. Bob and Wayne's, not so much. 

Bob's cowling started as an ARI, didn't it?  Maybe your cowling is comparable to the ARI in aerodynamics. 

Another reason I can think of is that as airspeed goes up, so does drag across the entire airplane.  The cowling mod might save a bunch of drag, but when the rest of the airframe is already generating more drag because it's already 5 knots faster, it's just not going to make the same difference.  

Just my $.02, I don't have any real proof.

[MIm20c]

8 minutes ago, bluehighwayflyer said:

158 KTAS @ 8.5 GPH @ 9,500’ pressure altitude.  

Jim

I can say to jump from 148 to 158 will cost me another 4 gph and will lower my range to as far as I can throw a ball. 

3 hours ago, David Lloyd said:

In another thread, someone asked about the speed of the F model.  Comments have speeds all over the place.  Same for the E and C. Looking at Flight Aware it would appear 140 knots for the C and F and 145 knots for the E are pretty common.  About the only mods where there seems to be a true benefit are the 201 windshield and cowling.  I have searched but have been unable to find where anyone documented before and after testing when modifications are done.  Seems faster, definitely is faster, a lot faster is not a test result.  Anybody do any real before and after testing?  

The only hard data I can provide is you might save 2-3 hours on a long trip compared to an old “slow” Mooney but I’m still in the black with the 2,500 hrs I saved on the build. 

I’ve been looking hard for a nice already built 7 or 8.  I haven’t found anything of quality under $100k yet.  To get another two seats would probably double the cost.  I’m starting a lease on another hanger this month, ideally an 8 like the one outside the Garmin OSH tent could fit inside. 

[gsxrpilot]

N6XM (may she rest in peace) was a 150+ knot TAS M20C. She had all the 201 mods including cowl, windshield, wingtips, etc, etc, etc. Very few antennas and nothing poking out through the glass, wings, etc. She was light for a C, with 1015 lbs useful load. She'd also spent some time in Don Maxwell's shop getting the brakes turned around and the rigging redone right.

It was pretty common for me to get 152 knots TAS. If you ever are talking with Don, ask him about 6XM. He'll testify that was the fastest M20C he'd ever seen or flown. 

There are also quite a few in the Mooney Caravan org who will also testify to her speed from having her on the wing keeping up with J's doing 150+.

Who knows what exactly made her so fast, but she was fast.

 

 

[ArtVandelay]

Ok, time to brag for Joe Dion's J... Here are the numbers and the proof...

The EGTs are well balanced, but the CHTs are awfully high for cruise? The #3 is low because it’s a ring probe (~30°), 2 are bordering 400°?! By comparison my highest CHTs run about 360°.

[carusoam]

We have one MSer with newly installed 10:1 pistons that likes to write...

Inviting @Sandman993 to the discussion...

Best regards,

-a-

 

[David Lloyd]

9 hours ago, Ah-1 Cobra Pilot said:

Those numbers are pretty close to theory:

KTAS              GPH                  Predicted % Increase     Predicted KTAS
155                  7.5                                    -                                   -
162                  8.5                                 4.3                                161.6
170                  9.5                                 8.2                                167.7
177                 11.5                              15.3                                178.7

It is always nice to see theory and experiment coincide. 

 

Filled a few pages with test data that back up theory.  Memory numbers might be rounded off or depend on how much rich or lean of peak but close, I did the tests, I got the numbers. I agree that in comparing before and after speeds you need to compare at the same fuel flow.

There does seem to be a lot of variation from one airplane to the next.  Same model, same mods, same fuel flow, different speeds.

CAS vs IAS is just a few knots but still a real thing.  Anyone else test theirs?  Yours high or low?  One airplane to the next could be different.  My IAS is 2.5 to 3.5 lower than CAS depending on the days I tested (many variables). I just use 3 and let it go from there.

Groundspeed is worthless as a performance indicator. 

Again, does anyone have their own test numbers before and after modifications. Again, years ago I found a number of mods that did next to nothing for speed increases. What works? How much?

[MyNameIsNobody]

10 hours ago, Sabremech said:

I didn't see any questions in your post. I'm moving on! 

Beat you on that one.  Already gone...

[mike_elliott]

8 hours ago, teejayevans said:

The EGTs are well balanced, but the CHTs are awfully high for cruise? The #3 is low because it’s a ring probe (~30°), 2 are bordering 400°?! By comparison my highest CHTs run about 360°.

yea, its amazing how fixing the baffle seal solved that.

[steingar]

A couple of my pals are touting the LASAR cowl closure mod.  Closes off the bottom of the cowl, improves airflow.  They're claiming several knots for 0.5 AMUs, and I have to admit one of the guys who did this easily keeps up with Js in his E, and I don't think it had that much more done to it.  Any other experiences?

I wish I could say I was flying the fastest C, it just isn't so.  I might have been able to say I flew the prettiest, but Bob Belville has me pretty badly beaten in that category as well.