Would Airplane Builders Be Interested in a Pneumatic Dimpler?

[Pmerems]

Cameron,

I just sent you a private message that I hope will help you with your project.

Paul

[rv7boy]

[quote=cgrossl]Don,
... But, from the regular C-frame pictures that I have seen, the structure looks pretty flimsy and my calibrated engineering eye (yeah right) tells me that a 300lb force that trys to open the c-frame up would cause quite a bit of flex. Did Old Yeller flex alot during operation?...QUOTE]

Cameron,
Others have surmised in these forums and in the old Yahoo Groups that the C-frame is flimsy, but after over 6 RV's being built with "Ole Yeller," she doesn't seem flimsy to me...and I used it on my empennage. It's easy to say it looks flimsy, but my Registered Professional Engineer eye (BSME and MSME plus Professional Engineer) tells me it ain't flimsy. I've seen some folks try to convince me it flexes using bending moment calculations, etc. If she were flimsy, don't tell all those folks who are now flying their RV's that their rivet holes were dimpled with a flimsy dimpler frame.
It's like Jay Pratt said on an earlier post, we need to be building instead of spending so much time on these PC's...so we can go fly!
Don
BTW, if it means anything, I am planning to buy one of Paul Merems's DRDT-2 dimpling frames. Looks like a good design to me. When I had a break in my building schedule due to my Dad's stroke and subsequent death, someone else needed Ole Yeller to start their RV-8. Ole Yeller is a loaner for our builder's group and she's sorta like Van's Ole Blue (RV-6A). She just keeps goin' and goin'.

[cgrossl]

Don,
I've been around enough to know that just because something looks flimsy, doesn't mean that it is. That's why I asked you if you saw alot of flex. You can caculate bending moments all day and you still won't get a better test than one in the real world. Just because the C-frame looked flimsy to me, doesn't mean that it really is. I've been wrong many times in my life and I'm sure that it will happen many more times before I die.


By the way, the "calibrated engineering eye" remark that I made about myself in an earlier post was meant to be in a sarcastic, poking fun at myself, tone, not an I'm smarter than everyone else tone. Just in case some took that the wrong way.

[jthocker]

I bought a Kearns metal works c frame pneumatic dimpler about 15 years ago. It was similar to an avery in that it was made from steel tube. It had a foot actuated switch, and about all it would dimple deep enough without flexing was .015 elevator skins. In addition to it's miserable dimpling capacity was the fact that I was faster with a hammer and the traditional c frame due to the time it took for the pneumatic switch to reset for another lousy dimple.
Jay's right, quit trying to reinvent the wheel, get off the net and get in the garage and build!!!

Jon
RV4, RV4, RV6A, RV8

[cnpeters]

I admire the innovation behind the original idea, but I see it as significantly inferior to a DRDT-2. Points supporting the DRDT-2 include:
1) DRDT-2 costs much less at $330
2) Practically no noise
3) Very precise teasing and control using my arm and a lever - can't beat thousands of neural processing steps via coordination circuits in the posterior brain that refines signals to the muscles of the arm as I sneak the dies together and slide the pilot hole onto the male die before compression. While I can gain a little teasing with a pneumatic trigger, it is tricky and far less smooth. That's why I've never punched an accidental hole with the DRDT-2 but have with the pneumatic squeezer. Even my 12 year old son has dimpled with the DRDT-2 - no way he is touching a pneumatic squeezer.
4) No compressor needs to be running
5) No speed advantage of a pneumatic dimpler (might be slower due to more care to ensure alignment of pilot hole and dimple die). I can average close to one dimple every 1.5-2 seconds on the DRDT-2.
So, having bought and used the DRDT-2, I just can't see how a more expensive pneumatic dimpler would benefit the homebuilder who only needs it in limited spurts. A mass production scenario might be another matter to mitigate that famous occupational health diagnosis of 'repetitive stress injury'.
Just my 2 cents, and I certainly laud your innovation and enthusiasm.