Wheel covers, Petton or otherwise

twheel47

twheel47

New member
Does anyone have (relatively) first hand knowledge of wheel covers? I have a set of (uncut) Petton fairings/doors and an annotated set of instructions from the STC, SA1019WE. They're a tad simplistic which is why some one wrote all sorts of notes and dimensions on another set which were used to install a set covers on N6575 in December 1971. The back of that 337 is unbelievably brief! I'd like to get some accurate measurements of the lengths of the three pieces when the single piece is cut.

Shortly after getting these, I spoke to two different people over the phone who had installed them and both avowed the Petton claim of 10-13 mph; one said "just over 10 mph" and the other man said that he was "just under a 15 mph" increase. Both said that the movable doors were not worth the effort to install of keep rigged and the speed wasn't changed if they were omitted. They found they were just as hard to keep rigged as the Viking doors so they removed them. Unfortunately the skimpy notes I made during these telephone call have been separated from the rest of my information so I have to rely on my memory!

One man installed landing and taxi lights in the very rear of the wheel blister ala later Vikings and said that didn't result in broken lamps from crud kicked up from the tires when I asked. He advocated that location to replace either the belly mounted retractable original or the wing mounted (Cruisemaster) modification.

Working with a customer's about 12 years ago, he formed a set of fairings that not only covered the attach points of the upper gear but also streamlined the strut upper end when the gear was retracted. We had no way of measuring any performance improvement since he was doing a complete restoration but he does have a very fast airplane. That sounds interesting too.
 
twheel47,
I'm sorry I'm a newbie here and in the Cruisair so cannot offer any support, I'm afraid I'm in the sponge mode. If anyone has the details twheel is looking for as well as a lead on molds for or the blisters themselves I'd be keen to add them to my to do list for HFM.

Cheers,
Andy
 
I had 2 sets and more paperwork than just the STC but it all burned in Septembers Valley Fire. The problem with the Petton covers was that the hardware was very weak and not mounted well if done by the instructions. I had some hardware from a set of doors for a 14-19-3 that I was going to modify for the aft swinging gear of our 14-13s, but too many projects put that on hold. Also the STC clearly stated that it was for that one plane only. One of the sets I had was from a 14-19 that the owner said was slowed down by them. In an old news letter from the early Bellanca club there was a photo of that plane doing a low pass and you could see a significant gap. The gap must have caused a lot of drag. I think Petton covers could be a nice improvement if better hardware is used, but fussy if the original designed hardware is used. I loaned one of my sets to Drew Peterson to copy and he sent them to a fellow in Texas who was going to make copies, and they ended up at someone elses place to be copied and finally after 10 or 12 years came back to me, only to go up in smoke. I dont know if anybody actually copied them. ______Grant.
 
I just re-read Scotts post and I believe that the original Pettons did fair the front of the upper leg when the gears was up. Pettons plane, still with the gear doors was for sale a while back in Idaho. Larry Bell had restored it and did a beautiful job. ____Grant.
 
Yes, the Petton covers fair in the front of he strut when retracted. The inadequate hardware problem and the doors being sucked open in cruise (also a Viking problem over the years) was what the two fellows addressed to me when they were saying to not install the doors. They found that the lack of doors made little to no difference to the performance.
 
Interesting stuff. I bought Mel Bolas' old airplane, N6575n, and it's in the process of being restored - Petton gear and all. After reading this thread I think I'll try without the doors before dealing with them. I have been told by a reliable witness that many hours have been spent upside down under the wings adjusting them.
 
P.S. Grant, you're correct. when retracted there is a fairing in front of the gear leg to smooth the flow.
 
Forrest, would there be any chance of some photos of the fairings and the hardware? Measurements would probably work for Scott. I think it will show how rather flimsy the hardware was. Modifying or engineering new hardware would probably solve the unwanted gap problem. Vikings also had problems keeping the doors tight, but the doors on the Vikings are huge compared to the Cruisair fairing doors. I just recalled the people that had my fairings. Randy Smith and Bruce Barton. I havent heard from Randy in years, but I recently talked to Bruce, so I will see if he actually made molds from my set. ____Grant.
 
Forrest,
Is there any chance that you will fly the plane withOUT the covers initially, then compare the numbers after you install the covers? I'd be really curious to know how much they give you. Thanks!
Larry Lowenkron
 
For what it's worth:
Back in 1974, Scott Twitchell finished the restoration on his 14-19 with the Petton fairings installed.
His set was the only one I ever saw that would keep closed and sealed at 150 mph. He was asked many
times "How much do they give you?" His answer was always "I don't know." At Oshkosh,1975 he had some
rigging problems on one side, so he removed that side and put it in the luggage compartment. On the way back to the west coast, he couldn't tell any difference with one off and one on.
As a result, he took off the remaining side and sold the set to someone else. Scott's statement was "I saved 27 pounds of steel and fiberglass." He always claimed he could not measure much difference.
Dan
 
For "What it's Worth #2"
It was in 1977 or 1978, Hank Kennedy out of Santa Paula, Ca. was attempting to STC the Petten Fairings for the 14 series Bellanca. During FAA mandated dive testing, his Cruisemaster plunged into the Pacific Ocean,
killing him and any dreams of an approval. Maybe Dan Torrey can fill in the details........
Dan
 
I ended up with Scott Twitchals Petton Covers, and the very flimsey hardware. That is the one that I saw the photos of the slightly open door and was told that they slowed the plane down. My information was 3rd hand, so take it for what it is worth. Hank Kennedys estate sold the molds and information to a fellow that (I think) ended up flying Cessna 180s, and didnt continue the quest for approval. I have heard differing stories about how Hank Kennedys plane was destroyed during the FAA required dive tests, and Hank dying in the bailout. It is a sad story, but when you are being a test pilot you take risks. There are probably many unfinished sets of Petton covers floating around, and I dont think they are at all unsafe, but dont work well with the poor hardware. That is speculation on my part, but if it wasnt for the red tape, I would be willing to put them on my plane , with sturdier hardware. ____Just another opinion. _____Grant.
 
I wonder what fixed fairings would do...probably better in that you wouldn't have to screw with the mechanism and weight. Even then, so you get 15 mph out of it...that's ~15 minutes on a 300 mile trip.
OK, speed gives you bragging rights.
 
Maybe the key to workable speed fairings would be something permanent on the Wing that the wheel retracts into, with a supplement fairing on the gear leg. That way you minimize the flimsy hardware and mechanism problem, and ensure they end up where you want then when the gear is retracted.
Maybe a modified cessna wheel cover approach?
 
Yes, that is what I was talking about. They were used on a highly modified 'Master that was at O22 a few years ago. Dan is very familiar with it. Still don't know what they did for the performance though. I think that plane had an IO 470 installed?
LL
 
Well gee-whiz Larry, what a bubble burster! Sometime the cold, hard truth is like that.

I have to admit that it would theoretically take about 45 minutes off my trip to Sun-N-Fun or to Blacksburg (AAA Fly-In) since I opt to limit my leg duration to 2- 2 1/2 hours for my butt's comfort. So, after the dust settles there's not too much incentive...... other than fun and curiosity.
 
I have seen Cessna 150 wheel pants mounted on the bottom of the wing of a Cruisair which the owner said helped speed, but no real testing. My own plane came with nice little fairings just in back of the retracted wheels, but I dont know if they made any difference. I took them off at the first annual because they seemed to cause friction getting the wheels up into the well. The previous owner had been running 500_6 tires rather than the required 600_6 that are normally on the Cruisair, and the fairings had been installed to clear the smaller tires. I wonder if there has been any testing on other planes to show if closed gear doors help very much??? _____Grant.
 
What I'm thinking of doing during the restoration is making sure the fairings mounted on the gear legs is a pleasing, smooth shape. I'll test fly then mount something behind the wheels. One thing at a time............ Of course, I'll be too old to calculate results by the time I have it ready.
 
In my opinion, you can do more for speed by reducing weight, very careful rigging of the control surfaces, flap gap seals, hiding all the antennae and smooth control. 392's ailerons were hanging down about 1/2 inch below the bottom of the wing. Yeah, it was a real pain to do the necessary wing surgery to correct that, but it's done and ready for cover now.
I was going to experiment with an air dam idea in front of the wheel well, but I'm not too sure I can even finish 392 now much less do any experimentation.
 
You must log in or register to reply here.
Back
Top