Would Airplane Builders Be Interested in a Pneumatic Dimpler?

[cgrossl]

Over the last few months, I have been doing alot of research on building airplanes, RV's in particular and I have decided to build an RV7 for myself. But, I am waiting until I sell my truck before I buy the empenage kit. I need the garage space.

Anyway, during all of this research I found it surprising that the most accepted methods of pressing dimples in a piece of sheet aluminum are with a hammer and a C-Frame jig to keep the dies aligned, or with the pull of a lever. I'm sure that both of these methods work well, but I work as a Machine Design/Manufacturing Engineer so my mind kind of defaults to figuring out ways to automate processes. Its almost a reflex now.

Since I can be kind of lazy sometimes, my first thought after finding out that you had to use a hammer or a lever to make a dimple in a panel was to use a foot pedal operated pneumatic cylinder to do the work for you. This would give the operator both hands to position the panel and wouldn't require him or her to have to over extend when dimpling large panels. Also, since the air cylinder would exert the same amount of force on the dies every time, dimples should be very consistent.

So, I sat down and designed a foot pedal operated, pneumatic dimpler. The preliminary design is complete and I should have the prototype built in the next month or so. It completely bolts together (No Welding), weighs a little less than 30lbs, has a 23" throat (to dimple up to 46" wide panels), uses standard 3/16" shank dies, and uses high quality pneumatic components capable of exerting 300lbs of force. The whole thing was designed using SolidWorks 3D modeling software. Cosmos Design Analysis software was used to evaluate the design to ensure that the unit flexes as little as possible during operation. We'll see how well I did after the prototype gets built. For some reason, everything looks better on paper than it does in the real world. Right now, retail price looks to be in the $350-$400 range for a complete kit the includes everything except dies and an air nipple. Assembly should only take about half an hour. I am also looking at producing dies. $35 seems like a whole lot of money for two little pieces of stainless steel.

So, what does everybody here think? Is this something that you would be interested in, or am I wasting my time?

By the way, if anyone here is looking for a good looking 1972 Chevy Truck, shoot me an email or PM.

Thanks,
Cameron

[Jaypratt]

Avery Tools has a foot air operated dimpler. Kinda spendy...
Vans sells a RV QB Kit to people that want an airplane, not a job. Very little dimpeling in that. Get a QB and fly sooner!! not later.

[rv9builder]

Cameron,

My EAA chapter has a foot-operated pneumatic dimpler that was surplus from Lockheed. We love it! Once you try it, you'll never want to use a hammer and "C" frame. It's one of the most popular tools in our shop.

[RV7Factory]

Aircrafters sells a giant yoke. I wonder how many they sell.

I am not affiliated with AirCrafters in any way.

[Rick6a]

Originally Posted by cgrossl

............This would give the operator both hands to position the panel and wouldn't require him or her to have to over extend when dimpling large panels........ It completely bolts together (No Welding), weighs a little less than 30lbs, has a 23" throat (to dimple up to 46" wide panels), uses standard 3/16" shank dies, and uses high quality pneumatic components capable of exerting 300lbs of force......the unit flexes as little as possible during operation.....retail price looks to be in the $350-$400 range for a complete kit the includes everything except dies and an air nipple. Assembly should only take about half an hour...Is this something that you would be interested in, or am I wasting my time? ........

Cameron,

Much of what you describe has for decades been in common use in the production environment. In addition, the concept is also frequently employed on the factory floor to set rivets, both flush and protruding.

Your design sounds interesting and if you can produce a high quality pneumatic dimpler/riveter and manage to bring it to market in the target price range you hope for, I say go for it and go for it in a big way. As one lister already suggested, its utility would be lost on the average quick builder but such a tool if properly designed and competively priced would have wide appeal in the world of amateur sheet metal aircraft construction, RV or otherwise.

I'm not convinced you can produce a reliable pneumatic tool that can measure up to the standards of the pneumatics out there and already enjoying widespread use. You'd be hard pressed to find many of those tools in basic form and new condition for the price you are shooting for especially since you mean to include the substantial and expensive throat accessory to be bolted to it and the floor frame to complete the assembly. My uneducated guess is such a design would of economic necessity have to cost much more than $400 for you to realize any profit worth pursuing.

Clever designs are developed by creative people all the time. However, as time has shown us again and again, it is one thing to design something that people want but a completely different set of skills and talents are required to make the transition from paper concept to hard metal creation and then compete successfully in the bare knuckles forum of the marketplace.

It is your vision. None of us can pretend to know what you are capable of. If you are convinced you can deliver such a product at the price you specify, AND after reading of its positive and glowing reviews in the aviation publications, I'll likely be placing an order and consider it the best $400 I ever spent.

[mlw450802]

Originally Posted by cgrossl

... It completely bolts together (No Welding), weighs a little less than 30lbs, has a 23" throat (to dimple up to 46" wide panels), uses standard 3/16" shank dies, and uses high quality pneumatic components capable of exerting 300lbs of force. The whole thing was designed using SolidWorks 3D modeling software. Cosmos Design Analysis software was used to evaluate the design to ensure that the unit flexes as little as possible during operation...

I think you'll find that the force required to make an acceptable dimple is considerably higher than 300 lbf, perhaps on the order of 5 to 10 times that.
Your frame will need to resist significant deflection at those loads. Make sure you fully know the problem you're trying to solve first. Otherwise an inexpensive air operated dimpler would surely be purchased by some.

-mike

[rv7boy]

Well, a lot of folks said it wouldn't work...but one of our TVRVBG (Tennessee Valley RV Builders Group) members modified an Avery C-frame with two small (Bimba) air cylinders and an off-the-shelf air operated pneumatic pilot valve. Place the clear tubing in the mouth, position the aluminum sheet on the dimple die, a gentle puff of air with the mouth, and Voila! A neatly dimpled hole.
There's no telling how many holes this particular unit (Ole Yeller) has dimpled, but a good estimate is that it's been used on at least 6 RV's...and it's currently on No. 7!
The designer/builder of the pneumatic dimpler was going to make his mod available as a retro-fit kit, but he put all his time into building an RV-8, and he's not interested now.
I'd guess he didn't have over $50 (plus the original C-frame) in this dimpler.
Don

[dpansier]

I have large Aircrafters yoke that I picked it up used at the fly market several years ago during Oshkosh.

The yoke is flame cut from 1? steel and weights 105 lbs. I set it up with a foot pedal air valve to a CP squeezer and it works very nice for dimpling. It will also squeeze small 3/32? rivets but flexes when squeezing 1/8?.

One caution, it is very easy to put dimples in places you don?t want them.


Don
D Pansier
Green Bay, WI
RV-7, Finish Kit
N450DP Reserved
VAF 586

[prporter]

I would be interested. I would be willing to pay $up to $200, to include shipping.

[szicree]

I think the big obstacle is the pressure required and the resulting deflection of the frame. Has anybody considered a device that automates the "whack" of the usual c-frame tool? I'm picturing a c-frame with something like a pneumatic nail-gun attached to the top. It seems that this arrangement would completely avaoid having to beef up the frame.