Engine upgrade

[Don Eide]

Re: Engine up grade

Don's Dream Machines
200 Barry Whatley Way
Griffin, GA 30224
1-770-412-8885

You can find his ads in Trade-A-Plane under Continental Engines.



Kevin,

Under the Type Certificate A-696
VI - Model BC12D-85, 2 PCL-SM, approved September 30, 1948
(Same as Model BC12-D except for increased power and gross weight, fuel system changes, auxiliary wing fuel tank, revised wing fittings and minor stuctural changes)

Harer's STC does most of this.

If you can drop in an 85, and get it approved without beefing up the wing, Good luck. But I don't want to ride with you.
Don

[Len Petterson]

Re: Engine up grade

I did fly in a 0 200 powerd experimental Taylorcraft.
about 800 ft.min rate of climb at 75mph. With 2 onboard!
Empty weigt about 820# if i remember rigth, it is ligther when mine at 833#
It is build with wider fuselage as well, and with original wings.
I it is a NICE bird, and it has a solar panel in the wingroot and a motorcycle battery for power. I am also using a 15 amp/hr motorcyle battery for my portable radio, intercom and GPS. I had to charge it 2 times this year. I have 3 cigarett ligther plugs indivualy fused, 2 amps, with LED indicator ligths and a masterswitch on it. It sits in a acid proff container. I should have used 6-8 amp battery to save weigh.
The 15 amp battery weigth is 10 #
(The continer is from a windshield washer fluid continer with wire for handel for easy of removal, with a holder permanetly monted on the back off the metal bagage compartment, secured with rubber load strap.)
Only in Canada?
Len Petterson

[matsuthunder200]

Re: Engine up grade

Dose anyone know if they are feild app, any type of motor upgrades. i have heard that they were not at all. I have a 90 hp in mine and had it app, with no problem at all but that was 10 years ago. I have a frind that wants to put a o200 in his 46 t-craft he has a 75 in it now.

[crispy critter]

Re: Engine up grade

Don,
I just want the extra HP,not the extra gross wieght,no electrics,no radios,no extra baggage.I live in the mountains of east kentucky where the runways are short,the terrian is high,and the summer time humidity stays at 100%.
I talked to lots of people when I started this restoration in 2000 and was told that it was just a simple bolt on upgrade with no changes to the airframe.My wings are completed.I did check the thickness of my original butt attach brackets and they are .091 steel on the front.I also did the one piece mod to the strut attach brackets.The only thing I didn't do was change the bushing sizes in the spars.Now if you can give me one reason why it would be unsafe to fly my bird behind a C-85-8 please tell me now!

[Don Eide]

Re: Engine up grade

Kevin,

The Harer STC does just that. In the STC for a BC12D-85, I didn't find any Gross wt increase. THe STC calls for a C85-8 engine with NO electrics, NO radio, NO extra baggage, NO changes to the fuselage. The STC only beefs up the wing attach parts. Its when you go to a BC12D-4-85 or Model 19 that you have all the work and extra weight of electrics plus plus plus.
In 1948 when T-craft put in the 85, they must have at least thought (maybe they tested it) that the wings needed larger bushings under the attach straps.
I just don't want anybody to go to all this work and then get hurt because they left out one part.
Don

PS. Put in a Don's Dream Machines engine which puts out 97Hp.

[gr8lnd]

Re: Engine up grade

Hmmmm, appears as if I jumped in to the BC12D upgrade toils and travails. Previous owner of my BC12D-85 upgraded to the 0-200 (longer mount, non-electric), but never pursued certification/approval. It has now become my concern. I'd be willing to go the distance to get a general STC (non-serial # specific) for the conversion as opposed to reclassing to experimental to get my Airworthy Cert. Word has it the FAA office here in Juneau is "accommodating and informative." Have a savy A&P willing to assist. Am I wishing for too much?

[crispy critter]

Re: Engine up grade

Don,
The Taylorcraft TC #696 says that the BC12D-85 approved in Sept 1948.What about the BC12D-85's that came out in 1947???Was these mods done to it.My 1946 BC12D already has the heavy wing attach(butt)fittings(.091),however the factory calls for 11/16" OD spacers in the butt end of the spar under the front butt fittings(same as the Harer STC)for the BC12D-85,model 19,and F-19.The 1946 BC12D(65hp)calls for 7/16" OD bushings.Now,my bird has 5/8" OD bushings which I have never found metioned on any t-craft.They are the same size that have been on it since at least 1952 because it has been in my family since then and the wings were never taken apart until I dismantled the burnt remains 2 years ago.I put everyhting back just the way it has always been.If I decide to replace the 5/8" OD bushings that are now on my new spars the I would have to completly disassemble the wings again to replace the bushings correctly.If I just remove the butt fittings and try to hand drill the holes then I risk getting it crooked or wollowing out the hole,it needs to be done on a drill press to ensure proper alignement.The bushings are the only thing that is not the same as the BC12D-85 or model 19.
So tell me,would you or anyone else do all that work just to go up one size on a bushing when you have no intention of increasing your gross wieght and if you do the gross wieght increase it would only be an increase of 80lbs.If you increase the gross wieght any more then you put it out of Sport pilot class,you also have to basicly do another complete rebuild on the airframe due to all the baggage,cowl,mount,and tail weight mods.I DO NOT want all of this.All I want is 20 more horsepower to help get out in the summer time.I want to keep it in Sport class so my wife can fly it too.So once again,can anyone tell me why I shouldn't try to get this approved?

[Garry Crookham]

Re: Engine up grade

Kevin:

Did you receive the 337 (I mailed it last Friday evening)?

Per the TCDS for 85 hp under TC696, I think the key is the statement that aircraft above serial number 12000 are eligible.

Garry Crookham
N5112M
Tulsa

[stormman]

Re: Engine up grade

5/8 ? 11/16?
Whats 1/16 amoung friends?
Don't try 3/4 though as it weakens the spar according to the x spurts

[matsuthunder200]

Re: Engine up grade

Kevin When i had my motor conv, done 75hp to 90hp i had them do the gross wt inc from 1280 to 1500. When they put the bushings in the wings it took about 30 min a side after the wings were off. how they did it im not shure. A faa frind of mine in anch told me that they will not feild approve any type of motor change unless it is done according to a stc. Pluss if its done by a stc all the paperwork is done by your macanic.

[crispy critter]

Re: Engine up grade

Garry,
I haven't seen it yet but I also haven't went through my mail since wendsday,I've been too busy putting finishing tapes on the fuslage of Crispy(hope to have that done today).I will look in the stack of mail before I go out to work on Crispy this morning.

Norm,
I like the way you think.

Lance,
I have a friend that is head of a GATO office(we'll not say which one)who will approve it on a 337 as long as I can find one instance where it has been done before and send proof,such as a copy of another 337.

[Don Eide]

Re: Engine up grade

Kevin,

You just changed the rules of the game. 5/8 Spacers??? Who, what, where??? From the factory????? In 1947???? Sounds like a very good question for Forest. Did they, or did someone else update it?
I think you have a bad tape measure, and they really are 11/16.
And you already have the heavy fittings????
I'd say your ready to go.

11/16 bushings. I only had the end rib off when I drilled mine out to 11/16. A machinist friend built me a jig to hold the drill bit straight so I could drill the holes with a hand drill. I've done one wing. One to go on this airplane, then I have another airplane to do it to.

You also mentioned "tail weight mods". I don't see anything in the STC about tail weight mods. Can you explain?

Don

[Yellow Duck]

Re: Engine up grade

We have been talking about C-85. What about doing an A-80 from the A-65 ? Wouldn't that be almost like an C-85-8 ? An A-80 would only be 9.4 % less power. Would you still need the wing mods or any other mods ?

Just a thought.

[crispy critter]

Re: Engine up grade

Don,
I have double checked and the butt end bushings are 5/8" OD.That is puzzling to us too.The thickness of the butt fittings measure as follows,the left is exactly .092 and the right is exactly .091 . The bushings that go under the front spar fitting at the strut are 3/8" OD as they are suppossed to be on a stock BC12D(A65).
As for the tail weight,I was refereing to the model 19 and F-19 upgrades.They require a longer engine mount and cowling to accomidate the starter & generator.Therefore weight must be added to the tail to balance the now nose heavy bird.
Yellow Duck,
I think you can do the A75 convertion with no airframe mods but I'm not sure about the A80.

[NC95842]

Re: Engine upgrade

I’m not saying I have an A80 or anything… but a 46 like mine overhauled as an a80 (different pistons and the a75 oil holes in the rods) with a the standard Sensnich prop, I would estimate makes about 72 hp at 2300 rpm because of the higher compression. (Source: the continental overhaul manual hp chart.)
That plane would fly better at altitude also.
That plane would fly 110mph cruse with just me in it.