201 Speed

[bumper]

Bumper et al, I'd be curios about your photos of the cowl fix. I'm taking my 1989J in for Annual next week, and was going to provide them with the Lake Aero cowl fix kit. Has anyone had experiences with whether this kit fixes the "cowling riding up" issue? Sounds like there might be some permutations of the kit to include "glassed in wedges." Have not seen that available commercially. Thanks in advance for the advice. Peyton

Here's some photos of the upper cowl portion of the fix. The first 2 show the hardwood wedges that are glassed in near the rear edge of the cowl. These butt up against two stainless "L" brackets (short lengths of 1/8" thick aluminum angle would work just as well) that are bolted to the underside of the upper firewall lip using #10 countersink screws. Bracket shown in pix 3, mounting screw on top is not clearly visible as it's covered with UHMW anti-chafe tape.

 

Near the front of the cowl there's an STC'd honeycomb reinforcement to prevent the usual cracking on each side of the "spinner bump".

 

 

 

 

bumper

[KSMooniac]

Thanks for the pics, bumper!  I like the wedge and bracket idea and think I'll add that to my cowl.  I previously had the LASAR kit installed along with a bunch of fixed camloc receptacles and I still have movement.  I'm afraid the strap was installed with the cowl in the wrong position, so it unfortunately doesn't do what it is supposed to do... I should have installed it myself but oh well.  The wedges look like a very elegant solution.

[ChristianGodin]

I had a 201, 1977 and IAS at 3000 was in the range of 145 and 148. TAS was allway over 155.

[Critter]

With a few hours under my belt in our 201 now, it has been a learning process.

I have found that my manifold pressure gauge was reading incorrectly, I am now finding that at 4500 feet I am seeing 145 IAS, did not work out my TAS, but it was good to have a tailwind and see 180 ground speed. This is running at 24" 2400 rpm. Very happy.

[rocketman]

Critter,

 

Back to your original speed question.  Take a look at your POH in the performance section.  My '78J says for 2000' MSL, 2400 RPM, and 23.6" MP, the airplane should true out between 149K and 153K.  Using the 2% rule, that would be 141K-146K indicated.  The range in speeds is for differenct weights.  Also, CG location could make a difference.  With a forward CG (front seats full and no bags) you'll need more down force on the tail which will also require more lift from the wings, both of which will increase drag.  Still, your 138K indicated is pretty close to the book value.

 

The values I listed above were for economy leaning, which by the way, is just about the worst thing you can do to the engine.  According to my POH, economy cruise is 25 degrees ROP.  Everything I've read says that is just about exactly the point of highest internal cylinder pressure and the highest CHT.  I would personally lean to peak EGT, LOP, or if you want to run ROP I'd go to at least 100 ROP.

 

I read a rule of thumb for the J that you might find interesting.  If you add the RPM in hundreds and MP together and get 47, you're pretty close to 65% power.  For example 2400 RPM and 23", or 2500 RPM and 22" or 2600 RPM and 21".  Also, if they add up to 50 you'll be close to 75% power.  2500 RPM/25"

 

 

Any ideas on the numbers for other Mooney's other than the J? Like the Rocket of Bravo?

[Mooneyjet]

What about "201" with tks, anyone have any input if there is much lost in true airspeed.