Robertson STOL

[minton]

Need Robertson STOL POH for 170B pertains to STC SA499NW. STC held by now defunct Seaplane Flying, Inc. Any information greatfully received.

[blueldr]

Interesting!!!

I've never before heard of the Robertson Stol set up on the C-170B series.
I've seen it installed on C-182 aircraft but didn't know there was one available for the C-170B.

I'd be interested in seeing a picture of the installation and data about it.

[minton]

As it turns out, Robertson only producted a "Leading edge kit" for the 170 not the whole enchalada.

[mod cessna]

Speaking of stol kits anyone have experience with these "gap" seals on a 170. They were on a 170B i was doing some engine maintenance on. They guy said they were per the stc.

[Robert Eilers]

It seems to me the design of the gaps seals depicted would defeat the designed effectiveness of the fowler falp.

[GAHorn]

Yep. The "flap-gap seals" depicted partially defeat the purpose of Fowler flaps.
Gap seals should be for the purpose of reducing leakage between the low and high pressure areas of the wing while flaps are retracted...not deployed. IMO. Properly-fitted Cessna flaps already do that when the upper wing skin closes the gap at the upper-forward flap skin.

[blueldr]

That appears to me to be about the dumbest set of flap gap seals I've ever seen. Why in hell have a set of Fowler type flaps and then negate the designed purpose?

[c170b53]

Just guessing, only testing would tell whether the effective increased area would offset the loss of lift and increased stall speed. From a practical point, I wonder how long and under what conditions the material would remain pliable and intact.

[n2582d]

... They guy said they were per the stc.

In looking at the FAA's website there are at least nine STC's for flap gap seals on the 170B. Do you know who has the STC for that fabric gap seal?

In your picture I noticed a bit of wear on the top of his flaps. If you're looking for a little business you might suggest he add some anti-chaff buttons to the top of his flaps. If you're looking for a lot of business don't tell him about these buttons; you'll get to replace the entire skins. Cessna SNL 93-3 allows for 20% reduced thickness on skins (in regard to corrosion anyway). I'm guessing that skin is .020" so allowable wear is only .004". Here's a link to previous discussion on that topic.

It also looks like there is an added access hole on the outboard end of the flap well. Does he have a 337 for that? If so, any chance of PM'ing me a copy?

[lowNslow]

These seem like the seals discussed here a while back in the following thread:
http://www.cessna170.org/forums/viewtop ... als#p13461
(Unfortunately, all the picture links are broken)

[mod cessna]

I just wanted to know if anyone had any flight experience with them.

[minton]

Mod Cessna,

I guess you don't get that you will be bombarded with some what off the subject responces when you post.

But! I'm chiming in on this one. Who ever came up with that mod surely does'nt get the "Fowler flap" concept. If it were a "simple flap" for drag it might help as stated creat a bubble of high pressure under the wing. But folwer as designed needs the gap to remain open to first enhance airflow (speed) over the flap and second to help re-direct the air direction when the flap is set at less than ideal angles to the relative airflow.

Next time you fly aboard a Boeing product sit just behind the wing a watch the show on takeoff and landing. Some of the early Boeings had a 40 degree setting for "Short field". Amazing how far the wing comes apart. But equaly amazing the "intermediate" slats to further help the airflow process. With the spoilers up and flaps deployed you can see Russia through the gaps!

I have seen a few gap seal mods that address the gap with flaps retracked to Zero degrees. It smoothes out the lower wing surface. When the flaps are extended it allows the gap to open and provide the nessecary airflow to the flap upper surface(being a fixed piece of metal). The most recent I've seen is on C-206's as a Cessna install. And as I have experience with flying that one it certainly performs well.

But I'll answer your question. NO! I have no experience with that mod.

[n2582d]

Need Robertson STOL POH for 170B pertains to STC SA499NW. STC held by now defunct Seaplane Flying, Inc. Any information greatfully received.

At this time I have been refered to the FAA aircraft certification office. They hold all STC certification work up papers. Some of the info contained in is not proprietory such as aircraft POH suppliments. My hope is that I can pry some of the info loose from them based on the owners not responding to my inquiries.

Minton,
I was going to suggest that you call the FAA certification office number listed on the STC but it looks like you already did that last year. I take it that was a dead end. Have you tried calling Sierra Industries in Uvalde, TX.? They hold the STC's for other Robertson STOL STC's.

[minton]

Talked to them long ago. He was very helpful and was able to dig up the original paperwork. It was then we discovered the facts. It was only developed for the leading edge boots not the whole STOL kit as was later Cessna models. Too bad for me