Brodhead Pietenpol Association

I'm considering this spring: https://www.grainger.com/product/RAYMON ... uty-44U753 The other possibility seems to be this https://www.thespringstore.com/catalog/ ... ategory/2/

Also looking at Lee Spring and McMaster-Carr for ideas

I'm not sure:

-how much weight will be on the the spring
-how much it should compress
-how long it should be when unloaded (airborne)

Thanks!

John C

Whenever it was time for me to figure out what spring to use there I got lucky and found a spring manufacturer 15 minutes from my house. The W.B Jones Spring Co. in Wilder KY. I stopped in one day after work with my drawings. I pointed out the note about the 6-7/8" length and being fully compressed to 1-7/16" at 190 Lbs. The nice woman there searched her parts list and came up with a couple options. I chose the C48-187-192. We walked to the back and pulled one off the shelf. I even got a quick tour of the factory floor and met the machine operators that probably made my spring! She charged me like $10 and I was on my way. As to whether or not the thing will actually work I can't say because I'm not flying yet. But I do feel good about my choice because I talked to an expert in person.
Also I've read in the past online that alot of folks are having good luck with a John Deere spring T143444. Last I checked though I seem to remember it being pretty expensive.

Update to this reply 11/6/22
The spring from W.B. Jones turned out to be a bit too weak and I could feel it bottom out sometimes. I switched to a Die spring from Grangier 44U556. It is working very well.

Thanks, I'll check that company. Ive seen the John Deere in discussion back to 2010, and it was $9 then. At some point they stopped making them. I can't find anything that compresses more than two inches. I may have to go to leaf springs if I can't find what I need.

John C

Here's what I bought from McMaster-Carr in July 2018. Picture attached. It's been working fine. I like the amount of give as I touch down.

Spring-Tempered Steel Compression Spring (pn# 96485K141), 6" Overall Length, 1.938" OD, 1.438" ID, $11.45
Die-Spring Cage (pn# 1878K57), 2" Long, 2" ID, $8.30 each.

Cheers, Ken

Thanks Ken! Great photo! What tailwheel is that?

John C

Looks like an Aviation Products (API) tailwheel. I hear good things about them. Also, Ken, I notice that you have some bellcrank extensions on your tailwheel. Was this done to slow down the response a bit? My Piet had similar extensions on the Scott 2000 but I found nothing in the logs during the airplane's test period indicating why Corky may have added the extensions. I flew the plane like that for awhile but now I'm using a Matco with no extensions and don't find much difference in handling.

Oscar Zuniga
Medford, OR
Air Camper NX41CC, A75 power

My tailwheel is the Lightweight Tail Wheel from Flyboy Accessories. It's a full pound lighter than the original tailwheel I had on my Piet. That might not sound like much but even a little weight saved on a long arm makes a measurable difference to the location of the CG.

I'm using the Doug Bell Tailwheel Fork. I like the geometry of the DB forks, as it helps the tailwheel ride up and over potholes and ruts in fields.

Yes, I added the bell crank extensions. I found that before I added the extensions the ground handling was way more "enthusiastic" than I wanted. The cable mounts for the extensions are now exactly the same distance apart as the cable mounts on the rudder horn. Now, the rudder and tailwheel move the same amount for each rudder pedal application.

Cheers, Ken

Great deal of information and all helpful. Thank you!

John C

John Deere spring #T143444

That's was the first spring I went to buy. John Deere doesn't have them anymore. Saw a company that sells discontinued stuff, but it was $100 IF they actually have it.

Hope your Piet project is moving along OK.

John C

I don’t want to step on anyone’s toes here but I just want to add my experience. I purchased the spring and die spring cages from MCmaster-Carr (suggested above) because the John Deer T143444 was very expensive at $89. (US). When they arrived they seemed heavy to me. As you know, the Pietenpol tends to be tail heavy and it’s important to do what we can to keep the CG forward of the aft limit. After asking around I sent the MCmaster-Carr spring and die spring cages back and paid the exorbitant rate for the John Deer T143444. It is noticeably lighter and I think will help keep the CG within limits. This is just my opinion.

Ended up buying McMaster-Carr 9657K557 Compression Spring, 5" Long, 1.46" OD, 1.086" ID