Throttle Cable Interference

How to keep the Cessna 170 flying and airworthy.

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2Georges
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Throttle Cable Interference

Post by 2Georges »

Hello All,

I just re-installed my throttle cable in my 1948 170 (currently under a long term restoration) and found that the center column of the control tee contacted the cable just prior to reaching the aft elevator stop. This causes the throttle to "bend" slightly to the left and put pressure on my new replica plastic panel. :( I then searched the forum and found the previous post by the same title. After reading through the posts, I have some questions.
1.) Did Cessna actully let these planes leave the factory with such a basic and understood interference issue?
2.) Does anyone not have an interference problem?
I should also mention that my throttle cable was replaced about 30 years ago. I was curious if the metal "sleeve", which extends about 7-8 inches behinds the panel when installed could have been shorter on the original part from Cessna. Any information is appreciated.

Andy
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GAHorn
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Re: Throttle Cable Interference

Post by GAHorn »

The throttle passes thru the panel with an angled-shim, to offset the cable to prevent this. See the IPC.
'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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2Georges
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Re: Throttle Cable Interference

Post by 2Georges »

George,
Just to be clear, are you saying that PN 0413150, which is called a "spacer" in my IPC is an angled shim? If so, it seems to me that an angled washer or shim would also be required on the front of the panel in order to properly tighten the throttle and avoid a side load on the plastic panel. I gathered that others had done something similar, but apparently Cessna just used a flat washer (AN960-A816L) on the front side. Any thoughts?
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GAHorn
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Re: Throttle Cable Interference

Post by GAHorn »

I'm sorry. I failed to note that you have a 48 model. The B-models used an adaptor, PN 0513004-16 (see Item 12) which is an angled shim to offset the throttle at a slight angle. If you look closely you can see it's not flat, but angled. Depending upon serial number, the throttle is angled up or toward the pilot to shift the cable away from the contol-T. You can accomplish similar results by using Adel clamps to reposition the cable so it does not interfere with the T.
You could also make a pair (for front and aft of the panel) from aluminum round-bar stock, drilled and cut on the angle.)
click to ENLARGE, Throttle Adaptor for B-models
click to ENLARGE, Throttle Adaptor for B-models
'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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Bruce Fenstermacher
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Re: Throttle Cable Interference

Post by Bruce Fenstermacher »

gahorn wrote: Depending upon serial number, the throttle is angled up or toward the pilot to shift the cable away from the contol-T. You can accomplish similar results by using Adel clamps to reposition the cable so it does not interfere with the T.
To be clear the throttle knob is pointed toward the pilot slightly but the cable still BARELY passes to the copilots side of the T. To be fair perhaps the cable passes farther away from the copilots side of the T with the angled adapters and neither of my two 170s had them requiring the artful use of adel clamps, tie wraps and bailing wire. In either case with my aircraft the throttle was not tight at the instrument panel allowing some angling in the area to take place without damage.

This is one area I thought the Cessna engineers blew it and the throttle cable placement must have been an after thought. It was probably late Friday afternoon when they placed the throttle and the rudder return springs in the blueprints. :roll:
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Bruce Fenstermacher
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Re: Throttle Cable Interference

Post by Bruce Fenstermacher »

I just remembered seeing a bracket in the IPC which helped to hold the throttle cable away from the T. It goes from the glove box to the cable. As the glove box has been removed in many aircraft chances are this bracket is as well.
I found the bracket 0413116-5 in both the A and B model IPC but the '48 IPC shows no bracket that I could find and 0413116-5 is not a listed '48 part.

From the B model IPC #70
Screen shot 2010-10-01 at 9.42.25 AM.png
From the A model IPC #105
Screen shot 2010-10-01 at 9.47.58 AM.png
Screen shot 2010-10-01 at 9.47.58 AM.png (28.32 KiB) Viewed 14857 times
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N4005V
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Re: Throttle Cable Interference

Post by N4005V »

Mcfarlane has the wedge spacer it is Part Number EC89 I used two of them one on the inside and one on the outside of the pannel. It moved the throttle cable away fron the control column very effectively. As I remember it was difficult to get the spacer wedges aligned while tighetening the nut.
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2Georges
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Re: Throttle Cable Interference

Post by 2Georges »

Guys,
Thanks for the input. I had a good friend of mine who is a machinist (very handy to have around!) fabricate a couple of spacers at 6 degrees. The install was just a little tedious, but worked out marvelously! No interference. By the way, I have a neighbor a couple hangars down with a !70B. I ran into him at the airport during the process and mentioned my problem to him. He said he'd never noticed such a problem with his bird but decided to take a look. He qickly called me down! Sure enough, each time the yoke was pulled back, both the control tee and aileron cable contacted the throttle cable, visibly bending the throttle to the left. There were also two respective wear spots all the way through the plastic/rubber sheathing! My friend made him a set as well. :lol:
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GAHorn
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Re: Throttle Cable Interference

Post by GAHorn »

(The following information is likely to enflame folks into posting tirades against gov't and FAA. If you feel so inclined, please take a deep breath and resist the urge. The purpose of making the post is to encourage the machinist, not to deter him, from making simple parts for owners.)

2Georges: Be certain to tell your friend, the machinist, that making parts for airplanes requires that the owner of the aircraft specify the materials, and participate in the quality-control at the very least, in order to qualify for "owner produced parts"....otherwise his activities may be illegal.

In other words... I am offering the advice that your friend require a letter or a signed statement from each person who desires parts, to ask for them in writing and describe them as subject to owner's-inspection. This is to protect your friend from accusations of making aircraft parts without proper certification/authorization.
'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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Ryan Smith
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Re: Throttle Cable Interference

Post by Ryan Smith »

Sorry for the thread resurrection.

I’m finally getting around to installing a glovebox back in 56D and would like some more information on the 0413116-5 bracket that Bruce mentioned above. It seems like an easy enough part to fabricate…just some dimensions and I’ll be good to go.

Can anyone help?

Thanks!

Ryan
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Joe Moilanen
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Re: Throttle Cable Interference

Post by Joe Moilanen »

Ryan Smith wrote:Sorry for the thread resurrection.

I’m finally getting around to installing a glovebox back in 56D and would like some more information on the 0413116-5 bracket that Bruce mentioned above. It seems like an easy enough part to fabricate…just some dimensions and I’ll be good to go.

Can anyone help?

Thanks!

Ryan
I just used a piece of 1/2" X 1/8" aluminum flat bar bolted to the bottom of the glove box with a #10 bolt, and an Adel clamp on the other end around the throttle cable.

Joe
4518C
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Ryan Smith
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Re: Throttle Cable Interference

Post by Ryan Smith »

About how long is it?
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edbooth
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Re: Throttle Cable Interference

Post by edbooth »

Joe Moilanen wrote:
Ryan Smith wrote:Sorry for the thread resurrection.

I’m finally getting around to installing a glovebox back in 56D and would like some more information on the 0413116-5 bracket that Bruce mentioned above. It seems like an easy enough part to fabricate…just some dimensions and I’ll be good to go.

Can anyone help?

Thanks!

Ryan
I just used a piece of 1/2" X 1/8" aluminum flat bar bolted to the bottom of the glove box with a #10 bolt, and an Adel clamp on the other end around the throttle cable.

Joe
4518C
Personal opinion, nothing should be Adel clamped around the throttle cable unless it’s there to help support the throttle cable.
Ed Booth, 170-B and RV-7 Driver
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Joe Moilanen
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Re: Throttle Cable Interference

Post by Joe Moilanen »

Ryan Smith wrote:About how long is it?
I can't remember off hand, probably less than a foot. Just enough to keep the throttle cable away from the control "T" slightly.

Joe
4518C
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Ryan Smith
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Re: Throttle Cable Interference

Post by Ryan Smith »

edbooth wrote:
Joe Moilanen wrote:
Ryan Smith wrote:Sorry for the thread resurrection.

I’m finally getting around to installing a glovebox back in 56D and would like some more information on the 0413116-5 bracket that Bruce mentioned above. It seems like an easy enough part to fabricate…just some dimensions and I’ll be good to go.

Can anyone help?

Thanks!

Ryan
I just used a piece of 1/2" X 1/8" aluminum flat bar bolted to the bottom of the glove box with a #10 bolt, and an Adel clamp on the other end around the throttle cable.

Joe
4518C
Personal opinion, nothing should be Adel clamped around the throttle cable unless it’s there to help support the throttle cable.
As best I can tell, that’s the purpose of that strap. I figure if I’m putting a glove box back in, it would serve me well to fabricate/reinstall that.
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