The International Cessna 170 Association

Want to make sure I’m reading the price correctly, $688 per pair of exhaust stacks?

Yes, I emailed Pat and Sybil thru the link on their post in order to place my order on record. I'm not expecting a reply anytime soon so it really doesn't matter to me when they finally read the email. If the required 20 orders are made, I suspect it's going to be awhile before the pipes are made.

Does anybody know how to calculate how much net thrust these new pipes will generate? Every 2 engine revolutions sucks 300 cubic inches of air thru the air intake lowering the pressure in front of the engine. Then fuel is added and ignited, expanding the mixture (by what amount?) while accelerating the gas out of the exhaust pipe pointing down and to the rear, same process as a jet engine. The original pipes point straight down so no net thrust, there has to be a net gain with these, is it measurable?

hilltop170 wrote:Yes, I emailed Pat and Sybil thru the link on their post in order to place my order on record. I'm not expecting a reply anytime soon so it really doesn't matter to me when they finally read the email. If the required 20 orders are made, I suspect it's going to be awhile before the pipes are made.

Richard, the pipes may be ready in a month. Sybil placed a corrected ad for the FlyPaper, yet to be published that indicates this. The change in the ad wording may mean either they really wanted to say they'd have the pipes in a month or they've felt there is enough interest to place the 20 pipe set order.

Yes Richard,the angle of the pipes improves take off distance and height over an obstacle as the thrust vector is now down and aft. Not just down as the factory stack where which only tightened the planes loop performance.

Yes, Richard and Bruce... but there's a Loss of Useful Load due to the increased weight of the longer pipes as well as the loss of lift/downward thrust from the Fangs!
(and another deduct from originality in the judging rules)

These things are tuned for added horsepower, right?

Yes, I think they are tuned to B flat.

Somebody (hint, hint, Bruce) needs to fab up some contoured flush inserts for the old fang holes that can be painted and bonded in place. Yes, I know every fang hole is a different size so we could send Bruce a tracing of each one and he can custom fab them. Please Bruce!

Bruce Fenstermacher wrote:I can not stress this enough. Pat and Sybil ARE NOT computer people. Yes they have an email address and offered it. I have sent and received email from Sybil but a phone call was always part of the equation. I get the impression checking email on an hourly bases or maybe even a daily bases, is not their MO. I could be wrong.

I would suggest an email so your order or intent to place an order is recorded and then a followup phone call.

Thanks Bruce, I will call to confirm.

Richard, you want me to fab custom inspection hole covers?
(You did notice Mile's comment about using these didn't you?)

They come with everything needed to install them?

mit wrote:They come with everything needed to install them?

TIm, if I ordered a set I'd expect it came with everything needed to install them. I've never heard different about Pat's kit. Now it also comes with STC paperwork. But your question would be one to as should you order so you know what your buying.

Bruce, I know how you like to fab parts, just thought you might want to make some patches too.

I got a reply from Sybil today saying the pipes will be made and they will let us know when they are ready so it looks like a done deal.

hilltop170 wrote:Bruce, I know how you like to fab parts, just thought you might want to make some patches too.

The most I'd do Richard is order 4 of these inspection covers shown. Then I'd take two of them and drill out the rivets to remove the steel spring. I'd take the two springs and install them on the other two covers at 90° from the original spring. Drill and install new rivets to hold the springs.

What you have then is what use to be called a heavy or high slip stream inspection cover. Of course if you can find them already made with two springs, just get them, but I couldn't find them.

4-prong inspection plate is Aeronca p/n 3639.
Wag-Aero
Univair
Knots2U
Aircraft Spruce

mit wrote:They come with everything needed to install them?

When I bought mine a couple of decades ago the pipes were the only thing in the box. I doubt that has changed

I got just the pipes about 4 years ago. You will need to fabricate a rear hangar. I ran a bar across the aft of the engine mount and hung the pipes from there.