Mooney M20J air racing technique

[Becca]

Quote: testwest

So, here are the results from jetdriven, called "Team Chaos" in the race!

RACE 201     TEAM CHAOS     MOONEY 201    FAC3RG       57 MIN 26 SEC    152.2 MPH       132.26 KTS

Interesting....any comments from the racers?

[Becca]

Quote: Becca

So I was the one actually racing this plane.  Byron (jetdriven) ended up leaving for work a day early and my other partner also had to work so I was on my own.  The workload for this race was high with only one pilot and if I do it again, I'm going to try to find a navigator.  I am suprised at the speed, actually, I frequently was looking at the G/S on my GPS and it was consistently in the 145-150 kt range (there was a head or crosswind for a substantial amount of the race, I'd guess about 90 miles the 120 mile course), so I was expecting a higher average in mph - on the last leg, I descended from 1000 ft to 500 ft and the g/s hit 180 kts.  To be fair, I'm not the only one - we put in 180 mph as our maximum speed guess and so did the plane they put in front of me, and I followed him by exactly 3 miles the entire race, perfectly spaced.  I flew WOT, 2700 RPM, full rich (if you backed off on the mixture at all, the CHT would start to rise up into the 390 range), burning an expensive 18 gph.  It was terribly bumpy out and I had some significant altitude fluctuations.   I used the autopilot on the two long legs to help control the altitude changes, but on the shorter legs on several occasions found myself climbing a couple hundred feet before I caught it (ouch, airspeed loss!!).   Usually this was caused by me looking down at the map or zooming in on the gps and not looking out the window - with WOT I had trimmed full nose down and the plane still wanted to climb, it required slight downward pressure on the yoke at all times to maintain altitude.  Also, I took a couple of the turns a bit steep and I think I lost some airspeed in the turns, I think next time I am going to shallow them out a little more in favor of less loss from the g's and better heading control.   Also its amazing that no one hit a bird during the race, they were *everywhere*!  There were actually a couple aircraft "incidents" that day, including a prop strike it sounds like.

What I want to know is where did he find these results?  They aren't posted on the air race web side.

[takair]

http://www.sportairrace.org/id405.html

Results posted here.  Sounds like fun.  We have a local handicapped race.  Did it a couple of years, but it is based on max sea level book values.  Older Moonies are not very competitive since they lied in those old books.  One year I was second fastest, but came in second from last.  This year Cessna 150s came in first and second, beating even a lancair.

[carusoam]

Becca,

Nice work, must have been a busy 57 minutes.

Best regards,

-a-

[carusoam]

Becca,

Nice work, must have been a busy 57 minutes.

Best regards,

-a-

[Shadrach]

Well done Becca! Sounds like a well executed first attempt...

[jetdriven]

Quote: JimR

[jetdriven]

We are protesting the results.  There is an error somewhere, and we think it is exactly 10 minutes, which makes her speed 152 knots, and that is 179 MPH.  Our declared index was 180, so there you have it.

 

It indicates 183 MPH with two people, perhaps smooth air and one person, 185.  That is about 180 MPH CAS.

Mooney's dont like low level WOT flying, they go faster and with 1/2 the fuel burn at 6000'.   We will enter the races again, and there are a couple drag mods we can do as well.

 

 

[jetdriven]

Quote: carusoam

Becca,

Nice work, must have been a busy 57 minutes.

Best regards,

-a-

[jetdriven]

We have though of that and I am aware that strobes count as anti-collisiion lights just like a Cirrus.  However, Houston has a large amount of traffic and that Whelen belly strobe is super bright. I like the red baron XP or something like that, but they are like 700$.  That's the ultimate solution.   We just bought the plane and spent around 5K fixing things and getting the aera, panel dock, and panel straightened up.   I did remove an old LORAN antenna and that had to be one knot.  I got two Comant shark fin antennas to replace the old "ball on a stick" transponder and DME antennas. I'd bet the belly strobe is another knot. If the LED collison lights come down much at all, we will likely get one.  The final antenna hurdle is the cat whiskers, I hate them. 

 

 

We havent heard back from the protest committee except he noticed our speed was alarmingly low, and seeing as how they calculated we finished two minutes longer than a C182L and 1 minute faster than a Cherokee 180, its going to be re-figured.   We have the track log from the Aera and it shows time over every waypoint.  Our aera mounts above the audio panel front and center, check my photos to see. I think we are the first to do it that way. Its a poor-mans 430.  We love it. 

[Becca]

Quote: JimR

Hey, Byron & Becca.  You can lose that belly strobe if you want.  My plane and lots of other 201s of our vintage were certified with just wing tip strobes.  Unless you live in a really high traffic density area or fly a lot at night, it is just extra drag, weight, and something else to maintain as far as I'm concerned.  An ounce of flat plat drag reduction has to be worth a pound of fairings and fillets.

Just FYI in case you decide to remove it, I have a round inspection panel there.  It is externally mounted with round head screws if I am not mistaken. 

What's the status of your protest? 

Jim  

 

[jetdriven]

Sorry, an old sailing and car racing term.  Protest means to contest the results.  

[Becca]

Double post.

[Becca]

The organizer emailed me and said my time had been entered incorrectly into their spreadsheet and was 10 minutes off.  They will adjust the results.  Anyway, that puts my time at 47:26, which my math says my average speed was 154.3 kts (177.6 mph). 

They also posted a picture of each plane on their web site (http://www.sportairrace.org/id407.html)  Here's mine.

[Becca]

Quote: Becca

The organizer emailed me and said my time had been entered incorrectly into their spreadsheet and was 10 minutes off.  They will adjust the results.  Anyway, that puts my time at 47:26, which my math says my average speed was 154.3 kts (177.6 mph). 

They also posted a picture of each plane on their web site (http://www.sportairrace.org/id407.html)  Here's mine.

[Hank]

Fly straight and level [no turns, much less pylons] on a standard day and see what you get. Either way, you're faster than me.

[jetdriven]

To update our progress, we have sped the plane up from 177 MPH to 193 MPH with improved flying technique and some airplane optimization.

 

Flying technique: The M20J is fast because it has low drag. It does not have the power the Bonanza's and other similar planes have and this really shows up in climb. So if you are going to go fast, you need to be smart about it and minimize your time spent climbing. Now, winds aloft play a big part in the air races and you need to optimize your climb profile to take advantage of it. The best climb strategy to get higher to net more tailwind is maximum available power, full throttle, 2700 RPM, and about 1400 EGT with a 360 CHT.  Second, the IAS is about 185-190 MPH during the event, and the best forward speed for climbing is about 5-10 MPH less than maximum. You just let it drift up. Now if you round a pylon and find a headwind, you descend 500 FPM or less, use the smaller gain in airspeed over  longer period to minimize drag from flying at high IAS.

 

Turns: anything over a 90 degree turn at the mark is done at 60 degrees of bank, but not a level turn, you lose too much speed. Allow the plane to drift down ~500 FPM in the turn which results in a net loss of around 200 feet for a 90 degree turn, about twice that for a 180. You basically smoothly bank the plane over a 3-4 second period to 60 but do not load the wing to 2 G's as you would in a level turn. Perhaps 1.3 G.  Allow the nose to fall 3-5 degrees below the horizon to maintain race airspeed, and then climb 100 FPM for 3 minutes with a very small speed loss for the next leg.  Smooth control inputs with minimal deflection is key.  For a 45 degree turn, a simple method is use bank angle to equal degrees of turn.   Your flight path over the ground should look like a parabola with the pylon at the apex. If you fly right at the pylon and then turn at the last second, your exit will be very wide, remember you are covering 3 miles per minute, or 300 feet per second.  You have to approach the pylon with 1500'-2000' of lateral room to make the turn, you turn radius at a 60 degree level bank, 180 knots is 1600 feet and takes .8 NM of flying distance, but since you are not in a 2 G turn, its perhaps double that. You approach the turn and when you have the apex, go for 60 degrees of bank. Your first few you will be really wide, you have to lead the turn to make the apex.  RH turns really need a copilot in these races or you will blow it and add an extra mile to your flight.

 

Flying pilot: Fly smoothly and accurately, nothing else.  Two hands on the yoke help along with your wrist on your knee.

 

Second pilot: invaluable for monitoring the  engine state, the flying pilot's course and altitude, watching for traffic, birds, radio calls, guiding the flying pilot into lateral position to make the next turn, calling the RH turns, monitoring the rollout heading and winds aloft / wind trade to maximize tailwinds and minimize headwinds.

 

Engine:  Horsepower to the crank is everything here, and make sure you are getting all you can. Full throttle and 2700 RPM, lean to 360-380 CHT. This is worth a couple and perhaps 5 MPH because you are making more power at the crank with a leaner mixture than full rich. Best power is 80 ROP but you cannot achieve that without melting something or running into heavy detonation. Don't even try it. However, you can lean in 1/2 GPH increments and let it stabilize for 2 minutes, then lean more until you get a 380 CHT then stop there. Watch it like a hawk.  The second pilot should be doing this as the flying pilot is, and should be, consumed with flying smoothly.  Ditch the Brackett air filter, which costs you 3 HP and 1/2" MP at full throttle, and get a Donaldson or Challenger air filter.  Ensure the throttle is opening to the stop.  Make sure your engine is turning the full 2700 RPM with an optical or digital tach.  Fly it for 5 minutes at WOT with the prop full forward to verify it. Mechanical tachometers read high often, and what you think is 2700 RPM is only 2625, and that costs you HP and speed. Ensure that baffle in the muffler is in good condition and not collapsing on you, that hurts exhaust flow. Supposedly they are not airworthy without the flame cone baffle in there but I know they are not slower with it missing. Make sure you have the full 25 degrees timing, or the 20 degrees as called for on the data plate, or some cheat and run 23 degrees on a 20 degree engine.  That Lycoming service bulletin has been beat to death on here, but the only difference in a 20 and 25 degree IO-360 engine is the impulse coupler on the left magneto.

 

Airframe: remove unnecessary antennas, and if you have draggy antennas, consider replacing them for modern antennas. We still had the "7" antennas which are pretty optimal (until one went bad, we replaced it with a Comant CI-196).  You can reduce drag from transponder and DME "ball on a stick" antennas with Comant CI-105 blade antennas.  Any kind of a rod antenna or whip antenna is a lot of drag. We replaced the ELT antenna with a Pointer model which was shorter, and raked.  We also removed the CI-122 bent whip LORAN antenna and a huge King ADF antenna, both were replaced with a flush patch.

 

Make sure your ball is in the center in cruise, the gear doors close tightly, cowling is aligned and not riding up as J cowls tend to do, and the engine mounts are not sagging. Check the spinner is centered in the cowling and there is no right thrust in the mount. You can shim the engine as Don Maxwell's article says to do. When its right on a M20J, the engine has 1/2" right offset at the spinner point and it has zero down thrust. The crankcase top is perfectly level with the airplane jacked to level, and the spinner gap between the cowl and the backplate is parallel.  The flaps and ailerons are all at 0 to -2 degrees and in line with each other.  Ensure the cabin and baggage doors close flush and the seals are not leaking.  Check the elevators, ours had a 2 degree split. Rig the cowl flaps to close tightly to the bottom of the cowling. Re-rig the tailpipe to tuck up into the tunnel on the bottom of the fuselage.  Ensure the prop is clean with no dings on it, and the paint is in good condition on the leading edge.  Wash and wax the entire plane with careful attention to the leading edge and the first two-three  feet. This wing is laminar flow and any contamination, dead bugs, even chipped paint, will trip the boundary layer and increase drag. There is a reason you lose 2-3 MPH IAS in rain, because the laminar flow is tripped.  Minimize that.    Ensure the roof scoop vent is closed tightly. and close the outside air vents.  Air in the cabin is air out of the cabin side vents, and that is drag.  You can tape the baggage door, side vents, scoop, and cowling but we elected not to because it strips off our old tired paint.  Get the CG aft.  Adding weight to the baggage area hasn't proved to pay off, but the flying pilot sitting as far aft as possible and the second pilot with the seat fully aft and reclined, sitting as far up on the seatback as possible does.  All of these little things add up to 16 MPH in this case, and there may be a couple more left in the old bird. We will find out.

[Super Dave]

Wow, Thanks Byron! Very thorough, useable and pithy. I've been searching several days for this kind of info, and you've just increased my knowledge ten fold in two minutes.

[carusoam]

Well researched and written Byron.

You're going to need sponsors for future improvements.

best regards,

-a-

[Super Dave]

Any updates on technique/strategy? I'm planing on entering my 76F in the Northwoods 100 next weekend. Specifically, I'm wondering about start and finish strategy considering this race has a flying start/finish at the departure airport. The finish seems pretty straight forward; I'll attempt to cross the finish line at minimal allowable altitude at the bottom of a gentle dive. But I'm not sure how to handle the start. As I understand it, we takeoff, climb to altitude while circling the airport, and cross the start line on a parallel taxiway. So, should I climb to the max allowable altitude while circling and then dive to the minimum allowable altitude as I cross the start. Or should I hold on to that potential energy and cross the start line at or above the altitude that I plan to fly my first leg at? It seems to me that crossing the start line at the bottom of a high speed dive is a wasting energy on a lot of extra parasitic drag, and that it would be better to slowly play out the extra altitude on the first leg, but I'm only guessing. What do you see the experienced racers doing?

[AlanA]

Ditto:  Make us proud!

[jetdriven]

Climb as much as possible at 70-80 MPH and make a nice wide turn before returning to the start line. The more air miles you can do before you cross the start line, the more energy you have built up in the form of altitude, you want 2000 AGL but 3000 would be better for a high altitude first leg. . Then, beginning 2 miles from the start line,  dive for the start, 1000 FPM and cross the start line at 180-200 MPH IAS at 1000' AGL.  If the first leg is a tailwind, cross the start higher, perhaps 2,000 AGL. Then you enjoy the tailwind the first leg without having to climb to get it.   If the first leg is a headwind, then minimum altitude and maximum airspeed, something like 500 AGL and 200+ MPH. Lower is faster there.  Finish the race at minimum altitude, if it is over a runway, start down about 3 miles out from 1000 AGL, go for the numbers, and let the airspeed wind up to as much as you can get and use ground effect, the airplane will keep an obscene amount of airspeed for a long time in ground effect. . In the J its usually 220 MPH. Then after the finish, do a 1.5 G pullup to 25 degrees ANU, roll crisply to 60 degrees, pull it through the turn and you roll out on downwind at 120-140 MPH and 1000 AGL.  If you get to 100 MPH, the manuever is over, dump the nose to the horizon and roll wings level. Then from there, normal ops.

[jetdriven]

Just busted the class record again, raised it from 192.54 MPH to 195.65 MPH. Becca completely bung holed one turn but did very well otherwise. The added mods were the wing root fairings, horizontal tail fairing, dorsal fin and seal, aileron gap seals, and fiberglass inner gear doors. We ran a race last season and turned in 188 MPH, but I suspected the fiberglass gear doors weren't closing properly. They weren't, and worse, they were flexing and opening under air pressure. I reworked the right door with some carbon fiber and completely re rigged the doors. I think the left door is now doing it some, I can feel some airframe tremor at 215 MPH IAS but I'll work on that. Dump the unused ELT antenna, install these new blade VOR antennas, fix the broken down flap hinge fairings, fill the wings for laminar flow and slap a fresh coat of paint on the old thing we might al see 201 MPH just yet.

Interestingly the big motor class at the Texoma air race consisted of a 520 powered S35 Bonanza, a worked over 550 A36, and a M20J 305 Missile. They all finished within 1 MPH of each other at 211 MPH. So we are losing 15 MPH to airplanes with 50% more horsepower.

One RV guy had a mag fall completely out of the case because he didn't get the message that you can't reuse the star washers when you adjust the mags. Do not reuse the star washers. He was flying around with one mag sitting on the engine mount and the motor turning 2900 RPM. He was lucky.

[Becca]

Mooney air racing technique: Let your wife fly. Nag her endlessly about making perfect turns for all 47 minutes when you are supposed to be navigating and making radio calls. Take to the Internet and tell everyone about your victory. Another fun race! Seriously guys bring out some 201 competition for us!

[Hondo]

After you have made the plane as fast as you can in level flight, what is the fastest way to get thru a turn?  

 

Here is some Red Bull footage.  http://www.wired.com/2014/03/red-bull-air-race-abu-dhabi/

Why do they make turns with more than 80 degrees of bank?

 

V = velocity in knots

B = Bank angle in degrees

Rate of turn in degrees per second = (1092.5*tan()/V

Radius of turn in feet = V^2/(11.26*tan()

Accelerated stall = SQRT(weight/gross weight)*SQRT(1/cos()

You can get thru the turn much faster at 80 degrees, with a shorter path and with less than 6 G's, than you can at 45 to 60 degrees.

 

I know Mooneys are strong, but Va is probably less than 120.  Is it safe?