Speed Mods

[Joshua Dickson]

Hi, I see other posts regarding speed mods but no conclusive evidence yet. I have a 59 PA-24 180 and am looking to get some more speed out of the old girl. What are peoples real world experience with the knots2u and Lopresti mods? I cruise at 140 @ 8k now and other than Metco wingtips she is pretty much stock on the outside. Any suggestions short of an engine change and a good wax job?

[Pat Donovan]

Zach Grant says the most cost effective is the flap/aileron gap seals. I got 3kts on my 180.

PatD

[N3322G]

Suggest good rigging, perfectly placed gear per Service Manual, well-balanced prop, engine mounts that keep engine steady and of course, best speed mod is more fuel for fewer stops (and a human element range extender).

Of course, finding tailwinds is free There was a very funny story about this told by a family friend about my Mom's, Marion Jayne, flying and always flying where the best winds were.

[Zach Grant L1011jock]

You can get 150+ kts out of a 180. All it takes is money (and a whole lot of work)! As Pat said the overall best bang for the buck is gap seals from K2U which include both the ailerons and flaps. If you are getting a real 140 kts TAS at 8k, you are already beating book speeds. Make sure you are really seeing an accurate number before starting the quest for speed. There are many ways to do this but the easiest is to just fly a big lazy circle at your constant altitude at no more than 15 degrees of bank. Note the high and low gps ground speed and average. That is your true airspeed. Most ASIs are woefully inaccurate unless they have been overhauled or replaced within the last 10 years. If you wish to discuss anything more fully my contact info is in the pathfinder and the flyer.

Zach

[JIMICS2452]

Go to Hansmiester's web sight (http://www.hdneubert.com/) and download the instruction on reversing the brakes to the inside of the landing gear and get them up out of the wind. Some labor and a 337 by your AI, but the lowest cost per MPH I have found.

[Mark Anderson]

Jim, I agree on reversing the brakes. It made the most difference for me. Also the slipper behind the nose gear is good.

Mark

[James N Bates]

Stopped at Knots 2U in Burlington, WI last summer and had them install aileron and flap gap seals on my 1965 260 Comanche. I had them paint the parts to match also. They did a good job. My observations are as follows. I did not see any increase in airspeed. Maybe 50 feet in climb (hard to tell). I feel that the low speed handling is improved along with my landings. I seem to be able to control the touchdown better. Maybe I am just closing my eyes a little earlier in the flare. The mod was worth the expense to me. I

[Zach Grant L1011jock]

I know this sounds a bit anticlimactic, but where you get your speed increases with the gap seals is at higher angles of attack, and opportunities when you need more wing. What this translates to is lower indicated airspeeds. So rather than trying to see speed increases down low at high power settings, go to an altitude where you can only get 65% power or less, and then look at the speed increase. Most people don't do a before speed under these conditions, but if you have a generally book speed aircraft, you can use the book performance charts to make your comparisons. In my case my aircraft with all the mods is only 7mph faster than book at sea level max power, but is 22mph faster than book at 11k and 34 mph faster than book at 16k operating on about 50% power. I hope this helps explain the above statements a bit better.

Zach

[James N Bates]

Zack, I do most of my cross country flying at 9500 to 12500. I do not recall any great speed increase. I was getting a knot or two above book cruise before the mod. Next trip I will recheck the speed at altitude.

[Joshua Dickson]

Ok, a little off topic but I just put in an E.I. Fuel flow display. WOW, what a difference. It really help you fly cheaper. Prelim. #'s show 7 gph lightly leaned at 2500ft at 130kts. 24/squared. I will fly it more this week and post some more #'s on speed/altitude/RPM/Temp/MP/GPH in a new post.

[N3322G]

Look forward to seeing the stats. Ain't technology grand?