Cowling bumps ( Tear-drops)

[Mikek]

Looking for the bumps that are found on the L-16 and others that give clearance for the shielded plug & lead. Bought cowling withe the holes aready in but not the bubble.

Mike K

[marklamon]

Mike, Univair or Wag has them. They are off of the bottom of tha boot cowl of a J-3. I made mine by using a grease gun and two plates of steel. I can take some pic's of the tool an the finished bumps and post them Monday night. If I remember right they were 25.00 or 28.00 each from Univair. Mark

[Mikek]

Mike, Univair or Wag has them. They are off of the bottom of tha boot cowl of a J-3. I made mine by using a grease gun and two plates of steel. I can take some pic's of the tool an the finished bumps and post them Monday night. If I remember right they were 25.00 or 28.00 each from Univair. Mark

Mark,

A picture or two would be nice, will also check Catalog again did not see them but will look at J-3 parts section.



Thanks

[marklamon]

I could not find them either. They do have the huge ones from the Ercoupe listed. I called them and the guy did not know so he put me on hold and checked with someone and said yes they had them in aluminum. I just had a hard time dropping almost 60.00 on such a simple part.

The tool I made is real simple. There are two plates of 3/8" steel. The first plate has the teardrop shape, the second plate has a grease fitting. Both plates measure about 4" x 6" . There are bolt holes in both plates around the outside edge. Sandwich a piece of 3003 Soft Aluminum Sheet in between the metal plates, bolt it together and hookup the grease gun. You can make the bumps as deep as you want but if you go to far the 3003 will break. I'll post some pic's after I get home from the shop Monday. Mark

[MIKE UTLEY]

GOOD MORNING MIKE, THE COWL BUMPS YOU ARE LOOKING FOR ARE WAG AERO CATALOG NUMBER 3694, AT A COST OF $15.90 EACH. WE CURRENTLY HAVE 5 IN STOCK. MY PHONE NUMBER IS 1-800-558-6868 EXT 142, EMAIL ADDRESS MUTLEY@WAGAERO.COM.

THANK YOU, MIKE UTLEY

[Mikek]

GOOD MORNING MIKE, THE COWL BUMPS YOU ARE LOOKING FOR ARE WAG AERO CATALOG NUMBER 3694, AT A COST OF $15.90 EACH. WE CURRENTLY HAVE 5 IN STOCK. MY PHONE NUMBER IS 1-800-558-6868 EXT 142, EMAIL ADDRESS MUTLEY@WAGAERO.COM.

THANK YOU, MIKE UTLEY

Still do not see them in catalog, but went an orders some, hope these are not the Ercoupe style.

Thanks,

Mikek

[marklamon]

Sorry it's a day late
Hope this helps!!

[Nathan K. Hammond]

Mark,

Cool jig, thanks for posting that!

Not to get off topic, but how much did ballancing the prop smooth things out? We've got a Cub that could use a little tweeking.

nkh

[joea]

Really glad you posted some photos! I imagined about the same thing you described but the photo tells it all.

Very good work!

Joe

[marklamon]

Mark,

Cool jig, thanks for posting that!

Not to get off topic, but how much did ballancing the prop smooth things out? We've got a Cub that could use a little tweeking.

nkh

Well, It started out .90 inches per second out of balance. (Very rough) It called for 60 grams of weight on one blade. That much weight is alot considering that a nut for the prop bolts tips the scale at 9 grams! I put three wraps of duct tape at the tip and it brought it down to .08 inches per second (slightly rough). I had planed to use the weight of the paint applied to the tips (more to the light blade) to finish out the balance.

But thats alot of paint. The next trick is to rotate the prop 180 degrees and try it again. I know that the paint (Polane T) is even on the prop and it tracks out perfect. I wont stop till I get .02 IPS or less.

Most props that I do start out around .24 IPS and end up with anywhere from 6 to 18 grams of weight to get it below .02 IPS. The worst one I ever did was on a Pilatus Porter it was 1.24 IPS and required 90 grams!

To answer your question it is one of the best things you can do for your plane. I get alot of positive feedback, almost everyone that I have done the pilot has noticed quite a differance.



I guess if someone needs the cowling bump jig we could pass it around. I would like to have it shipped back to me while not in use. It could use six more smaller bolts around the outside to keep the grease from sneaking out. Let me know if you want them. Mark

[marklamon]

MikeK, Did you get the bumps from Wag yet? I hope hey are not plastic!

Update on the prop balance. I flipped it 180 degrees and it was .06 IPS! I changed out some thick washers for thin ones on the propbolts and got it down to .02 IPS. Mark

[Nathan K. Hammond]

You'll have to ask MikeK.

.02ips Wow.

nkh

[big chief 48]

mark..hi, where can a person go or call to get this done? How much does this cost? (ballpark) You are right about having this done to help the longevity of all the internal bearings!!!

[marklamon]

mark..hi, where can a person go or call to get this done? How much does this cost? (ballpark) You are right about having this done to help the longevity of all the internal bearings!!!

Big Chief, We charge $260.00 for a balance. We use the ACES system . I'm sure there are others out there. You could contact http://www.acessystems.com/contact.htm and ask them if they have any contacts in your neck of the woods.

Along with helping the engine it keeps your airframe, fairings, spinner, baffles, ect from developing cracks from vibration. MArk

[marklamon]

You'll have to ask MikeK.

.02ips Wow.

nkh

Oh yea I knew that.