landing gear/gearbox information

How to keep the Cessna 170 flying and airworthy.

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Roesbery
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Post by Roesbery »

A few years ago I took both gear legs out, one went under the other went out. neither came through the floor.
n4517c
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Post by n4517c »

The reason people in this area started changing the nuts without substituting the bolt is twofold. Examination of ground loop damage often showed the bolt deformed but the nut failed and it is so easy to replace the nut since you don't have to hoist the plane. One 185 ,which had the larger nut ,was recently damaged in a high crosswind incident. The plane went along the runway with the upwind wingtip in momentary contact with the ground and the ski axle tip damaged by runway contact. The nut held. That's only one incident but it is encouraging.
zero.one.victor
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Post by zero.one.victor »

Tom Downey wrote: When the gear is overstressed to failure with the mod installed, it vertually rips the flap handle out thru the bottom of the aircraft.
Tom, I don't get it. How does the flap handle tie into the gearbox? Or does the whole bulkhead rip down and out?

Eric
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n2582d
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Re:

Post by n2582d »

n4517c wrote:One easy way to strengthen the gear attachment is to replace the original AN365-720 nut with the heavy version of AN363 all metal locknut.
The heavy AN363 takes an 11/16 wrench. It has an axial strength of 18,300 pounds and is 25% stronger than a AN365. You end up somewhere between the origional and P Ponk and the nut costs less than a buck.
Yes, choose your nuts carefully: NTSB report
Last edited by n2582d on Tue Feb 09, 2016 5:43 am, edited 1 time in total.
Gary
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GAHorn
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Re: landing gear/gearbox information

Post by GAHorn »

GOOD ONE, GARY! Few people realize that all aircraft hardware is NOT the same.

As for all the nay-sayers about Pponk mods who claim it's better to rip out the gear in a minor mishap instead of it ripping out only in a major mishap: If you guys can tell me how hard you intend to hit a brick wall while driving... I'll tell you whether or not you'll need a seatbelt and/or air-bag! Doh!

As for me, I'm enthusiastic about Pponk.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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edbooth
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Re: landing gear/gearbox information

Post by edbooth »

I think y'all just need to land the airplane correctly and you won't need any of that stuff.....having said that, I installed the P.Ponk about 25 years ago.... :D The plane has survived two minor ground loops, both fortunately off the runway onto wet grass. :oops:
Ed Booth, 170-B and RV-7 Driver
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GAHorn
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Re: landing gear/gearbox information

Post by GAHorn »

edbooth wrote:I think y'all just need to land the airplane correctly and you won't need any of that stuff.....having said that, I installed the P.Ponk about 25 years ago.... :D The plane has survived two minor ground loops, both fortunately off the runway onto wet grass. :oops:
Well, there ya go!

But the nay-sayers overlook the fact that there's no control-group on this matter. There's no telling if your two minor
events wouldn't have been major without your Pponk mod.

Ground loops are like gear-up accidents...there are those who have ....and there are those who will.

I thought I was immunized years ago... then I tried to give a tailwheel checkout to a guy I considered a talented pilot who'd have no trouble at all.

Checking him out in my Aeronca Chief (no right-brakes) ...we watched the world go round-and round. 8O
Fortunately the wingtip only got within two inches of the ground. Whew! :roll:
He must have finally figured it out tho', because years later I saw a pic of him flying solo alongside a camera-ship in a Stearman. (Unless he'd rollled upside-down and dropped the other guy out!) :lol:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
Harold Holiman
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Re: landing gear/gearbox information

Post by Harold Holiman »

C180 N92CP (Clark's Plane) was formarly (Harold's Plane). I had a P Punk kit that went with the plane when I sold it that I had never installed. I did not know about the heavier nuts at the time.
Harold Holiman
Member # 893 (11/73)
Past Director, TIC170A
Former Owner of;
C170A N9027A
C172N N1764V
C180 N92CP
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GAHorn
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Re: landing gear/ gearbox info

Post by GAHorn »

Aryana wrote:[... And it's not like these are one of a kind airplanes. There's a large supply of nice 170's available at any given time, and I'd rather write a check to buy another if mine bit the dust instead of trying to repair a really bent up airframe.
I disagree with that presumption. There are NOT a lot of these airplanes out there which will pass MY REQUIREMENTS for NO CORROSION! (I don't think Steve Jacobsen or Rusty's are for sale at prices the insurance company will pay. I know mine isn't.)

There are lots of airplanes that cosmetically look fine. Many are fine examples of airworthy C-170s., some of them available in the $40-%60's range.
But, .. FEW are truly and completely corrosion FREE with recent heavy-airframe disassembly/inspection for defects.

While the insurance company thinks most 170s are the same...they are NOT. And I don't want to lose my airplane because I took a long time to find it....and I've got it just exactly like I want it.....and I don't think there's another one out there too much like it that's affordable.

Just my opinion.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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blueldr
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Re: landing gear/gearbox information

Post by blueldr »

Aryana,
That's cheap for a Rocket, but most of the Rockets that I've seen had Lyc. 540 engines. That four bangar couldn't compare.
BL
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blueldr
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Re: landing gear/gearbox information

Post by blueldr »

By talking about a "Rocket" I just assumed it was a "Harmon" Rocket, like the only ones I've seen, a sort of knock off of an RV 4
BL
bagarre
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Re: landing gear/gearbox information

Post by bagarre »

Yes, a Harmon Rocket is an RV-3 or RV-4 that's been modified with a separate kit to accommodate an IO-540 8O

The one in the link looks like a very nice RV-3 with a slightly beefier motor. The RV3 was designed for up to an IO-320 so, putting a 360 in it would make it an even better performer but not something to hang Harmon's name on (IMO)
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n2582d
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Re: landing gear/gearbox information

Post by n2582d »

I find it interesting that Cessna went from an NAS147-34 bolt at the inboard end of the gear on the '48 to using a weaker AN7-20A on the later models.
Gary
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ghostflyer
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Re: landing gear/gearbox information

Post by ghostflyer »

I change my undercarriage bolts every 500 hrs or after a very harsh landing . I always torque my bolts up and have found one once very loose . After a very close inspection [dye penetrate used] of the gear box section the nut on one the attach bolts appeared to have its threads compromised . New NAS 147 bolts and An 363 are now always used. P plonk is not used in my aircraft .
Reason being if P plonk is used the area around the gearbox where the spring attaches is beefed up and if after a heavy or harsh landing and if there is any damage to be done the forces are transmitted then on to the weaker areas of the fuselage. In board of the rudder pedals attach points and the tunnel where the flap handle resides are is where cracking of the sheet metal have been found in the past in other aircraft mostly 180,s . Hard to prove it’s because of Pplonk but it’s nearly always because of this mod .
marathonrunner
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Re: landing gear/gearbox information

Post by marathonrunner »

Guess I posted this reply in the incorrect forum. I copied and pasted it. Cheers

I agree with George with how hard do you want to hit a brick wall. However these STC/mods need to be an analyzed a bit better before being incorporated.

Unfortunately, I work on a lot of Cessna 180/185 aircraft...far inferior to the 170 due to the ever failing trim system and the stinger tailwheel. I can write volumes but will keep this to the Reader Digest version as opposed to the Michners version.

I think we can all agree that energy cannot be created or destroyed. It just manifests its way to the next weakest point. I do not have pictures to share now as I am not home, but convalescing after a major accident. There are tailwheel conversions for the 180/185 and I will not say the STC holders as I have already had lengthy conversations with individuals at the ACO responsible for the STC. They have larger wheels and tires which make it "better" for off airport landings without ripping off the tailwheel. Unfortunately the forces manifest themselves into the airframe and end up making the holes larger to the point of failure for the rudder bellcranks where the tailwheel springs attach and also wow out the tail stinger attach points. The tailwheel also becomes loose on the stinger.

It becomes a point of what do you want to fail more, the tailwheel or the rudder bellcranks which will then not allow steering? I have sent many examples to the FAA and written many useless MDF reports.

The solution for the individual responsible for the STC holder is to make a statement in their documentation to inspect these areas. The bellcranks are difficult to access even with panels in the fuselage.

Not a 170 issue but again when you reinvent the wheel and make it better there is almost always a consequence.
It's not done till it's overdone
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