C90 and short mount

[jCandlish]

What are the recommened STCs for the installation of a starterless C90.

PITA to fly hot and high enough with the A-series engine.

Thx
jC
.

[astjp2]

Re: C90 and short mount

There are none for that exact configuration, most were modifications of the Harer STC. Tim

[Ragwing nut]

Re: C90 and short mount

We did a 90-8 install by 337 about 15 years ago on a neighbors T. I do not remember the n number at this time

[astjp2]

Re: C90 and short mount

It wont happen any more, since about 2002, it is required to be an STC if there is greater than a 10% increase in Horsepower. Too many accidents with aircraft with larger engines installed with field approvals it what the FAA told me a few years ago. Tim

[jim cooper]

Re: C90 and short mount

Ahhh, typical FAA thinking! Now I ask those more informned, HOW could changing a 65 hp in a T-CRAFT to a 90 or an 0200 cause MORE accidents. I would think there would be less! All these little airplanes were underpowered at birth! JC

[astjp2]

Re: C90 and short mount

It has more to do with the idiot that wants to put a Merlin Rolls on the front of the taylorcraft or a 220 Franklin on a cub. Most of the field approvals back in the day never had any oversight, things like .049 wall tube compared to .058 wall. If it looked good, it flew. No structural analysis was performed. Some producers of the field approvals would say I dont really need that extra tube or extra gusset or that wing support flange. They had several accidents in the late 80's to the end of the 90's especially with few helicopters that had larger engines installed that killed the field approvals. Tim

[kona4breakfast]

Re: C90 and short mount

Thread resurrection: anyone else running a C90? My normal IA is out of pocket and the new one I'm using has a different read on which propellers are legal. Gilberti STC was done with a 337 for the C90. Left unmentioned in the 337 was anything to do with propellers, and that puts me in an odd place.

[astjp2]

Re: C90 and short mount

Ok, what prop are you trying to run? the C-90 can run up to a 75" diameter prop in a sea plane configuration and the original taylorcraft could run a 74" on land so you would be limited to 74" diameter, with static being limited by pitch....but you need something to back it up...

[kona4breakfast]

Re: C90 and short mount

I'm trying to solve two problems. 1. the 337 didn't alter the AFM to reflect C90 operating limits, and all of the gauge markings are for a C85 as well. 2. the 337 also didn't mention, at all, anything about propellers. It puts me in a bit of a gray area, apparently.

I am hoping to fix those issues, and in the process get approved for a Catto or a Sensenich 2EK/C72AE.

The question for the forum was just to see what other people had up front and how that was handled on the 337.

[astjp2]

Re: C90 and short mount

Well the Catto is not certified yet so the sensenich is a model that I am not familiar of, is it wood? Just do an ammended 337 updating the operating limitations. how long ago was it modified? Why is this IA doing a conformity inspection? the 337 is not a big deal, you are just bring it into conformity for a previous modification by unknown persons. I have friends in Anchorage that can help you out if you get in a bind. Tim

[kona4breakfast]

Re: C90 and short mount

Then Sensenich is a composite ground adjustable prop, hollow core. Apparently the issue with the new props like Catto and the LSA composite props is that they aren't built using any sort of production approval, this from an ACO person I was put in touch with. Apparently there's a new reg coming out soon and I think all the manufacturers are in wait-and-see mode.

I don't have an issue with my IA this year, I made it through just fine. I was planning to amend the operating limits but figured I'd try to get a few more props approved, which is why I asked to see what folks with a C90 were swinging.