BloomerJohn wrote:My MT source owns STC's for nearly a dozen A/C to use the MT prop. Each one took nearly 18 mos to get and between 40K-50K. FAA is real picky on tests to grant 337 on props. A tremendous amount of vibration, stress and endurance testing must be done, both on test stands and on actual A/C of the type being applied for. He would get the 337 with 15 confirmed orders. He would be at about a breakeven point at that number. Many peolple have asked him to get 337 on various aircraft, but usually this interest ends with the request for a non-refundable deposit from 15 buyers.
John
Any idea if there is an STC application fee? Or is there no cost except for having to conduct the testing? Does the FAA have specific engineers you have to pay for their time to review the STC submission?
The costs of testing and manufacturing are simple to grasp, but so far I can't get an answer on any government fees. I guess I'll call the Milwaukee FSDO and ask them, they oughta know since they are "the man".
Tye,
It seems all the costs are involved in renting test facilities, hiring engineers to evaluate and report on test results, needed to satisfy the FAA's engineers. I will ask if he has to also pay the FAA to read and evaluate his proposals.
Remember, you can put one on, but you would need to declare your 170 an experimental a/c and accept the risks and rewards associated with that action.
John
If you were to install that propeller and change your registry to "Experimental", it would have to be for "Developement" and you would not be able to use the airplane for anything except flights pertaining to the designated 'Development". Your flights would be restricted to a forty mile radius from the designated airport. You would lose any sort of utilityof the airplane.
For the kind of money you're talking about, you could put in an engine that would accept a CS prop.---and have more power too!
If you're thinking about engine originality, a CS prop sort of negates that anyway.
There are existing STCs for Continental, Lycoming, and Franklin engines that all use CS props.
The way I feel about it? $9K will buy a lot of gas.
Or a lot of beer. Or a bunch of gas & a bunch of beer
and maybe a steak or two. For flights within my state (98+%
of the flying I do), I typically show up 20-40 minutes behind my
180 buds right now, and that's fine with me (they already have the
best camp-sites picked out, the coolers are already out of their
airplanes, full of beer, and the fishing poles are in the process
of being rigged).
Like anyone else, I'd love a simple 2-speed/position prop on my
170, but I'm not about to fork over $9K for one. I'd rather
take the back seat out, pick my camping gear out carefully and
show up 20-40 minutes behind everyone else.
If I absolutely had to have more performace, I'd sell my 170,
keep the $9K, add another $10K to it and I'd buy an early C-180.
BloomerJohn wrote:Tye,
It seems all the costs are involved in renting test facilities, hiring engineers to evaluate and report on test results, needed to satisfy the FAA's engineers. I will ask if he has to also pay the FAA to read and evaluate his proposals.
Remember, you can put one on, but you would need to declare your 170 an experimental a/c and accept the risks and rewards associated with that action.
John
Thanks for the info John. I'm pretty interested in where the costs are in the STC and PMA processes. I have always read about how expensive it is but no one breaks it down. Not enough people really appreciate how much it costs to fabricate parts, replacements or new stuff like CS props, for our antiques and make them available for us to buy when we need them.
I had a talk with Tom Anderson (XP Mods) several years ago, he told me he used to do all his IO-360 installations on field approvals. Then the feds told him it'd be so much easier for everybody if he got an STC. OK, he thought, but the more stuff he did, the more they wanted him to do,eventually he had so much time & money into it that it only made sense to just keep on until they were satisfied. I got the feeling if he was to do it again, an STC wouldn't have been in the cards. Of course, this was back before field approvals were the big taboo they seem to be now at most FSDO's.
Here's a consideration: McCauley designed and obtained a type certificate for a constant speed applicable to the O-300 many years ago. It was not a commercial success for several reasons.
1. Aircraft utilizing the O-300 were lower-cost aircraft which did not have as much appeal when their purchase price was increased by addition of a constant speed prop.
2. The specific model O-300 (B) which had the necessary oil porting in it's crank and provision for a simple governor was not commonly installed/available. Therefore...
3. No OEM offered it as a standard option.
Now comes MT who wants to produce one.
Since previous mfr's were required to obtain type certification, it is logical that subsequent mfr's will be required to undergo the same requirements....if for no other reasons that to avoid accusations of partiality. But...many years later...despite the original popularity of the O-300...with much fewer O-300's flying than ever before....there are far fewer aircraft owners today than ever before who would be willing to spend the money on such a mod. And there are no potential mfr's who intend to produce new aircraft using an obsolete/out-of-production engine such as the O-300. There just ain't no market.
And I've never found an original, ground-adjustable, two-position McCauley as originally approved for the airplane which (it would seem) would be much less expensive to go back into production. No market.
(Lots of guys like to look at and talk about exotic girls but much fewer are willing to actually pony up with the money.)
'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.
N170BP wrote:No wonder Tom gets $4K-$5K (forget the exact number)
for the IO-360 STC.
Dealing with the feds must not be cheap (we all know it's
certainly no fun....).
The price ties in directly with what George is talking about too. There is very little hope for sales volume for an STC or PMA part so the R&D and development costs have to be recouped over very few parts. Which naturally raises the cost per unit. If the STC/PMA holder gets lucky and volume exceeds expectations then they are rewarded for taking the chance and financing the project to start with.
I'll tell ya, after my brief foray into finding streamline tubing for '46 140 jury struts I have a much keener appreciation for the people producing the parts we do have available.
George I'm real interested in that church bell spinner. Sure looks sleek !
keep us posted on that prop It would be nice to have the power on t/o and then push cruise up a little also. I would be looking for a 0300-D rather than the 220 I'm working on. N2628dD Gene
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