Low TAS Revisited

[airkraft]

I posted earlier that our E model was truing out 8-10 Kts slow.  Well, with the expert assistance from Scott and Al at Arapahoe Aero (an MSC) in Denver, we've resolved the dilemma.  Not sure which "fix" resulted in the restored airspeed, but here's what we did:

-  Positively disconnected the PC system to ensure no unwarrented control inputs or system binding were causing undue drag.  Both tail servos had torn vacuum bags, although the two in the wings appeared intact.

-  The vacuum operated retractable step was inop.  Again, a tear in the bag.  Used to be able to find individual parts to fix the system.  Now, as I understand, the whole unit needs to be shipped to Brittain in Tulsa for overhaul at a cost of several hundred dollars.  Anyone had any experience in this regard?  We secured the step in the retracted position to be sure it was not contributing to the airspeed problem even though consensus is that the step adds little, if any, speed penalty.  I do prefer having the step to get in and out, though.

-  Made adjustments to the rudder/aileron interconnect system.  There are two springs left of the "aileron horn" that became unequal in their inputs.

-  Added a washer to the slightly loose aileron horn assembly.  Probably did not affect airspeed or aileron rigging, but the control yoke has a noticably smoother, crisper feel.

-  Re-rigged all control surfaces using Mooney factory jigs.  Ailerons were within tolerances, but we rigged them to equal 1 degree down.  Elevators were checked.  Don't recall if they required adjustment.  I suspect the rudder was most of our problem.  Book calls for 2 degrees right of neutral.  The boards showed it was rigged 3 degrees LEFT.  We were able to take out most, if not all, of the very excessive trim tab adjustment.

Wow! What a difference.  We're back in the yellow arc below 10,000 feet.  Climb is much improved, as well.  Although I've only flown twice since the adjustments, three true airspeed checks at 8,000, 10,500 and 14,000 feet all were above 150 KTS true.  Hope this post is of some value to the group...GK

 

 

[Seth]

Great News!! 

I though my Mooney was slowing down for some reason this summer (I thought it was an engine problem), but then when I took her flying last week when the temperatures fell, boy did she have an extra bounce in her step.  The airspeed indicator was the highest I've ever seen (and ground speed was pretty quick too).  I didn't fly in a triangle to figure the exact true airspeed, but on my out and back course, and with the known winds, I think it may have been the fastest trip I've ever taken.  In my 67 M20F I was getting better than 150 knots true airspeed at 6000 feet (not ground speed)!  I've never seen the guage with a reading that high at that altitude unless I was in a dive - this was level flight.  I even turned on the pitot heat to ensure it wasn't blocked by ice (below freezing at that altitude).

I was pretty pleased to say the least. 

Hopefully your post and all the little fixes will help others diagnose issues and get their well deserved speed back.

[Immelman]

150KT true @ 14K is pretty darned good. I can manage about 140KTAS at that altitude, at 2500RPM.

I doubt I would get another 10 knots by going up to max RPM. Perhaps I should check out my rigging.

 

Do you have any speed mods on your airplane?

[ArtCraft]

ArtCraft Paint, Inc has a Thanks’ giving special COMPLETE PAINT JOB FOR $ 9,000.00 if you bring your aircraft before Saturday November 14, 2009

[Cruiser]

These numbers would be much more useful if they included the MP, RPM and mixture settings.  I can only assume WOTx2700 rpm and 100°F ROP which is maximum performance for most of our engines.

 

Today I was at 5000' eastbound 23MPx2300rpm @ 35°F LOP 144kts KIAS 172kts GS. burning 8.4gph just over 20 mpg !!

[airkraft]

Good points, Cruiser.  I cruise WOT, 2500 RPM, 30 degrees target ROP.  Don't have electronic fuel flow capability. Will try to record OAT's, MP's and GS's (although, don't really see how GS is relevant) for subsequent posts. 

Immel, I do have a 201 "style" windscreen (SW Texas Aviation, I believe) and the Scimitar two blade prop.

I would highly advise all Mooney owners to carfeully check rigging...GK 

[LFOD]

Quote: ArtCraft

ArtCraft Paint, Inc has a Thanks’ giving special COMPLETE PAINT JOB FOR $ 9,000.00 if you bring your aircraft before Saturday November 14, 2009

[MooneyMitch]

Hello LFOD.

Based on my experience with the nice folks at ArtCraft, I would say their post on the this thread is probably a mistake.   In my opinion, certainly not an attempt at spam.  I will speak to them tomorrow.

Incidentally, I've enjoyed watching your IFR posts on YouTube. 

 

[fantom]

Please do talk to them, Mitch, because the same exact post at least five times, under five different topics, at the same time, is classic  

[LFOD]

Quote: Mitch

Hello LFOD.

Based on my experience with the nice folks at ArtCraft, I would say their post on the this thread is probably a mistake.   In my opinion, certainly not an attempt at spam.  I will speak to them tomorrow.

Incidentally, I've enjoyed watching your IFR posts on YouTube. 

 

[GeorgePerry]

This issue came up before with the same poster...Opinions vary on the usefulness of businesses touting their wares.  Forums can be overrun with "spam" posts from companies trying to drum up business if some control mechanisms are not in place.   

I do believe there is benefit in having "Mooney friendly" companies support the community.  I think a better venue for this type of communication/advertisement would be a stand alone "Vender" section in the main forum topics.  

I'm not opposed to businesses letting us know about needed goods and services but the "pile on" method that this poster is using is inappropriate  

 

 

[Mooney13]

I agree with the special "Vendor" area for advertising. I personally am not bothered by a guy offering a very good deal on a paint job. Obviously business is slow at that price and I hate to see quality general aviation sources disapear...but I do understand that spam could get out of control. How about that "Vendor" section. Sounds like a great idea.

 

[mjc]

In addition to a vendor area, I think a classifieds area would also be useful. I'd certainly welcome a place to advertise parts and avionics that might be of use and I'm happier to do that here than elsewhere. It's a small community, so the odds of the sale going smoothly are greatly increased, and it's a Mooney community, so the odds that someone needs something I've got are higher.

[Guest Anonymous]

This is getting a little off topic, but I agree with the last two posts on Advertising and Classified areas in the forums. I would even go a step futher and have two areas for classified, one commercial and one for used parts and alternate or conversion parts only with no display advertising.