Beefup with P Ponk

[Watkinsnv]

Well I took a look at the P Ponk kit no.PSK1101 and for the price and what it does I put it ahead of whats next on the accesserizing of my 170B. I have an add in for a used pair of Altee Dodge rear jump seats. I have a baggage door w/stc that I'll install along with making an extended baggage compartment that will need a field approval. Finding the seats at the right price will take awhile so I'm going to go with the gear beefup now. Along the way I need to research the installation of the Century 1 auto pilot in a 170B, so I can install the one I have in mine. Lance

[cessna170bdriver]

Along the way I need to research the installation of the Century 1 auto pilot in a 170B, so I can install the one I have in mine. Lance

The Century I is already approved for the 170B. Go to http://www.centuryflight.com/ and click on "STC's.

Miles

[Watkinsnv]

Yea those sob's want a GRAND for that STC. NOT!

[zero.one.victor]

Good luck with finding a used set of Atlee-Dodge (or BAS) folding jumpseats. I looked for quite a while, & ended up buying a single RH jump seat out of a 180/185 ("divided middle seat assembly"). Installed it under a field approval 337. They don't fold, but you can find these Cessna factory jump seats fairly cheap, lotsa 180/185 guys sell them off when they install the spendy Dodge or BAS folding seats. The backs do pull right off, and the seat itself comes out by removing 2 bolts, so while it's not quite as handy as a folder it ain't bad.

Eric

[GAHorn]

Yea those sob's want a GRAND for that STC. NOT!

Perhaps it's not your intention to really deride them so, but... I don't feel they're entitled to be called such a nasty name for being in business to sell their product. The STC is their intellectual and corporate property. The use of the product without the STC is not legal, similar to the illegal use of a patent without paying the patent fee, or the operation of a Cessna without a datatag or airworthiness certification.
In any case, it's possible that if the equipment is already installed in your airplane that the installation already is licensed via STC. A tail number change can confuse that issue, if the original STC paperwork addressed only the serial number or if the paperwork was simply lost.
Have you tried asking them if they have a record of your equipment installation? I've run into similar situations where for a small fee of only $20 the STC holder will re-issue current paperwork on a previously approved installation. (P-ponk, B.A.S., and others frequently do this as a service also, in case paperwork is lost or if tail number has changed, etc.)
(I once owned a Baron which had no paperwork on it's Tactair autopilot. The current STC-holder is a commuter airline pilot and his family in Ohio, and when I contacted them regarding the situation, they simply mailed me a copy of the STC without charge. (Of course, I was also buying a rebuilt gyro from them simultaneously. Perhaps they just considered it good business.))

[spiro]

while you may have a hard time finding used Atlee Dodge or BAS seats, you can probably find used Pponk beef-up kits. Many people think they're a bad idea and remove them.

oh, and Atlee Dodge sold out to Univair. So it might be better to buy those seats now, before Univair "adjusts" the price.

- paul

[GAHorn]

That's not something I'd be easily convinced of. I can't imagine who in their right mind would deliberately tear back into a healthy airplane's gearbox to remove a beefup kit, just to add additional labor and rivets to refill the holes?
The idea of such a thing must stem from the argument that some folks (who are reluctant to install the pponk) make that a ponk-equipped airplane will be more torn up (if it is wrecked) than a non-ponk airplane.
It seems to me that there's no valid comparison. As an example, ...if you can tell me how fast/hard you're gonna smack the brick wall....then I'll tell you if the 5 mph bumper on the front of your car will prevent damage or not. The aircraft which supposedly are "wiped out because they had a ponk kit".... would have been wiped out anyway due to the severity of the accident. Theres no apples-to-apples comparison possible.
I'm convinced the ponk beefup is a great and valuable addition to the airplane. (In any case, obtaining one that's been salvaged and installed without the proper documentation/STC is a matter of integrity for the owner to decide upon.)

[spiro]

I don't know how many 170's George has rebuilt or even how many wrecked ones he's seen. There's no question that when a gear leg comes out of a Ponk'd airframe a major chunk of the fuselage comes with it. Without the kit it may just take the outer doorpost skin. It usually damages more but the Pponk guarantees the worst.

the Pponk beef-up kit does exactly what it claims; The gear leg will not come out of the "castings". So the load (and damage) is transfered further into the airframe. In a Ponk'd wreck the only thing you can be sure survived undamaged will be the Pponk beef-up itself.

I liken the bolt that holds the gear leg in to a boat propeller's shear pin. If you hit hard enough to break that bolt or strip the nut then you're probably better off letting the gear leg go than really tearing up the fuselage. Knowledgeable proponents of the Ponk kit think the margin between pulling out a stock-attached gear and causing deeper fuselage damage w/ a Ponk installed is big enough to make it worthwhile. In my experience if you screw up bad enough for a gear to come out, then it's coming whether Ponk'd or not.

Steve sells a lot of these, so obviously many people are convinced of their utility. We wreck a lot of airplanes up here and many rebuilders who see them come in both Ponk'd and not will not reinstall Pponk kits when they go back together - it makes their job easier the next time. Lance, if you're interested in a set of used Pponks pm me.

all that said, I reinstalled the Pponks in my 170 on the last gearbox. Only 'cause I already had them and I think there's some utility in them for handling the side loads of routine ski operations.

- paul

[GAHorn]

I don't know how many 170's George has rebuilt or even how many wrecked ones he's seen. There's no question that when a gear leg comes out of a Ponk'd airframe a major chunk of the fuselage comes with it. Without the kit it may just take the outer doorpost skin. It usually damages more but the Pponk guarantees the worst.

the Pponk beef-up kit does exactly what it claims; The gear leg will not come out of the "castings". So the load (and damage) is transfered further into the airframe. In a Ponk'd wreck the only thing you can be sure survived undamaged will be the Pponk beef-up itself.

I liken the bolt that holds the gear leg in to a boat propeller's shear pin. If you hit hard enough to break that bolt or strip the nut then you're probably better off letting the gear leg go than really tearing up the fuselage. Knowledgeable proponents of the Ponk kit think the margin between pulling out a stock-attached gear and causing deeper fuselage damage w/ a Ponk installed is big enough to make it worthwhile. In my experience if you screw up bad enough for a gear to come out, then it's coming whether Ponk'd or not.

Steve sells a lot of these, so obviously many people are convinced of their utility. We wreck a lot of airplanes up here and many rebuilders who see them come in both Ponk'd and not will not reinstall Pponk kits when they go back together - it makes their job easier the next time. Lance, if you're interested in a set of used Pponks pm me.

all that said, I reinstalled the Pponks in my 170 on the last gearbox. Only 'cause I already had them and I think there's some utility in them for handling the side loads of routine ski operations.

- paul

You make some interesting points, Paul. I consider myself a "knowlegeable" proponent of the Pponk mod, but I don't subscribe to it because of the reason you suggested. I subscribe to it because I believe that Pponk may save a "minor" screw-up from becoming a major one! It appears you and I agree on that matter.
I don't agree with the boat's shear-pin analogy however. Shear pins are designed to fail to protect a gear train in the lower unit. But I do not believe Cessna deliberately designed the landing gear to rip out when minor landing errors occur. I believe Cessna actually did NOT expect customers to make such errors.... and that is why they did not make the landing gear attachment any stronger than they did. Clearly they did not expect the inner gear leg to be required to stand up to upwards movement that occurs when say, the airplane makes a high-speed swerve to the left...and the right gear tries to fold under the fuselage. Pponk definitely strenthens the gear's ability to handle such problems.
As for my personal experience, ...no, I've not repaired any Cessna's that have lost the battle with bad ground-loops. But I've seen lots of them, and I have a video of Air Force L-19's (same landing gear design as the stock 170)) landing and folding the downwind gear underneath the fuselage with the result that the airplane subsequently drops onto the ground for the expensive slide, simply because the gear was not held good enough at the inboard end. The accidents certainly look survivable, if only the gear had been beefed up a bit more. I believe the Pponk would have handled the accidents I've seen on video. The wheel was only hopping a little bit when suddenly the inboard gear leg ripped out and folded under and the airplane fell on it's side. According to the video, the airplane was a write-off, which leads me to believe it was uneconomical for even the Air Force to repair that non-Pponk airplane. This seems to argue against the idea that a non-Pponk airplane is not damaged so much as a Pponk would be in the same accident. (The gear-box and fuselage are not the only damage when these sort of accidents occur. When the airplanes collapse onto the ground in a sideways manner, the wing outboard end is extensively damaged, as is the strut in many cases, and sometimes the tail also are heavily damaged, and the engine and prop are seriously damaged since they are actually running at the time of the collapse, with the rotating prop grinding to a halt against the ground. Any additional damage to a gearbox as the result of Pponk strengthening is only a minor portion of the total repair...which...might have been completely avoided if only that gear had not ripped out so easily.) IMHO

[mrpibb]

I installed the Pponk beef up because I don't like stupid things to happen. Knowing the gear attacth point to be the weak link, all I need is my gear to collapse due to a minor side load. I know a really good whack will cause more damage but I look at the odds. I fly into a lot of grass fields and some of them I do J takeoffs, so my gear side loads are more then the average takeoff. Plus when I got my airplane I wasn't certificated yet so when I started flying the 170 I had 1.5 hrs as a private pilot, so my aircraft needed I felt a little better odds, A fighting chance.

http://www.sandhillaviation.com/pponk1.jpg
http://www.sandhillaviation.com/pponk2.jpg

[Metal Master]

I was actually offered a P PONK copy for free and turned it down because of the STC and proprietary rights of Steve. However I would install an approved one right now for the following reasons if I had the extra cash on hand. The following link to Tailwheel.com shows pictures of my 170 repairs that I have been doing after my purchase of the aircraft having been ground looped by the previous owner. I have been doing sheet metal repair on aircraft for years. The very first 1st ground loop I performed some 20 years ago did not have the P Ponk mod and the attachment of the bolt to the inboard gear attachment fitting still ripped the entire fitting out of the airplane taking out the bulkheads, floor board, door post and belly skin. My 170 did not have the P Ponk mod and the damage is similar and the pictures show the same damage as in the 185. My conclusion is this in the worst side load situation the gear may be ripped out. The P Ponk mod will not necessarily limit the damage. But at least a broken bolt is less likely to cause damage. And the inboard attach bolt is very much less likely to break with the P Ponk mod.

It is interesting that the only thing left holding the gear attach brackets the outer ends of the gear bulkheads and all of the attaching structure was one high shear rivet through a piece of sheet metal aft of the gear box.

I have made a lot of progress and short of completing the small repairs to the control surfaces and the stabilizer the airplane is almost ready for final assembly.

http://www.tailwheel.com/forums/index.p ... m&album=45

[johneeb]

I was actually offered a P PONK copy for free and turned it down because of the STC and proprietary rights of Steve. However I would install an approved one right now for the following reasons if I had the extra cash on hand. The following link to Tailwheel.com shows pictures of my 170 repairs that I have been doing after my purchase of the aircraft having been ground looped by the previous owner. I have been doing sheet metal repair on aircraft for years. The very first 1st ground loop I performed some 20 years ago did not have the P Ponk mod and the attachment of the bolt to the inboard gear attachment fitting still ripped the entire fitting out of the airplane taking out the bulkheads, floor board, door post and belly skin. My 170 did not have the P Ponk mod and the damage is similar and the pictures show the same damage as in the 185. My conclusion is this in the worst side load situation the gear may be ripped out. The P Ponk mod will not necessarily limit the damage. But at least a broken bolt is less likely to cause damage. And the inboard attach bolt is very much less likely to break with the P Ponk mod.

It is interesting that the only thing left holding the gear attach brackets the outer ends of the gear bulkheads and all of the attaching structure was one high shear rivet through a piece of sheet metal aft of the gear box.

I have made a lot of progress and short of completing the small repairs to the control surfaces and the stabilizer the airplane is almost ready for final assembly.

http://www.tailwheel.com/forums/index.p ... m&album=45

Jim have you any current pictures of the progress of your project.

[Metal Master]

[quote="johneeb


Jim have you any current pictures of the progress of your project. [/quote]

Yes I have but I have been so busy repairing others airplanes I have not been able ot find any time to sit at the computer and post them. I will get around to it soon as I hope things will slow down.

Jim