Adjusting Washout

[Guest]

Re: Adjusting Washout

Prewar vs. post war measurement for the wing attach fittings after a repair? Wing spar fittings were off a little on each side? Does it really matter if you can get it to fly wings level? I would be looking at getting a prop before worrying about the wings....Tim

I agree. The problem statement has moved around a bit during this thread IMHO.

There are are interesting issues with wing rigging that came to light.

But if the real question is about speed the prop seems odd.

I run a McCauley a 70-49 on an A65. A 70-40 is too flat for an 85 hp.

Would be interesting to know the static RPM for this setup. I get 2040 to 2100 from year to year with optical tach.

Limit for the set up that I assume we are talking about is 2350, not under 2170

Since the ASI is alleged to be correct I would also look a W & B just because it intrigues me.

Dave

Dave

[astjp2]

Re: Adjusting Washout

Dave, your prop is too short for the 65, minimum is 72.5...

[astjp2]

Re: Adjusting Washout

That is not a true statement, the seaplane prop goes to 75" on some aircraft with the same engine that the land plane is only 72" max diameter... I know that the C-150 for example has a 68" on land and a 75/38 on water....and the cub has similar requirements...It was a ground clearance issue not balance or vibration one. Tim

Apparently the 74 inch prop is not certified/tested for vibration at the higher RPM of the 85. There was quite a discussion here on that subject a while back. Lot of people are using them anyway. Additional vibration would have to be pretty bad to notice it in a Tcraft. Chuckle.

On the full opposite adjustment on the struts; I have close to that condition on my -85. What I can see on my wing is that one of the wingtips is shaped slightly different from the other. I have to look VERY closely to see the difference. With all that leverage, for sure that is part of the reason for the adjustment offset on mine.
DC

[3Dreaming]

Re: Adjusting Washout

I thought the standard 150 prop for land was 69x50.

[astjp2]

Re: Adjusting Washout

67-69" for the 1a101GCM, 68 was the middle of the road....

[senior]

Re: Adjusting Washout

I agree on the prop comments.
I run a 72-42 Sen on my 85-8.
Cruise is about 80-85 on floats @ 2400rpm.
Motor will run past 2700 if you leave the throttle all in during flight!

The other problem I see is weight, 894lbs empty is brutally heavy IMO!
Any idea what the extra is from?
My plane is 775lb on ski's with 8-10 gls of gas.

[Robert Lees]

Re: Adjusting Washout

...My plane is 775lb on ski's with 8-10 gls of gas....

And

...
46 BC-12D Taylorcraft

Really? 8-10 gal is 48 to 60 lbs. I didn't think the wheels weighed that much compared with skis. I pared my 46 BC12D down to a realistic minimum (albeit with skylight and the two wing tanks) and I came out at about 815 lbs empty.

My pre-war that I used to own (lighter than the post-war as we all know) was 777lbs empty of fuel.

Rob

[Guest]

Re: Adjusting Washout

Dave, your prop is too short for the 65, minimum is 72.5...

Tim,

Yes, normally it would be too short.

But is not to short for this airplane because it has been properly modified by a field approval in 1998 for this prop.

Dave

[flyguy]

Re: Adjusting Washout

Someone give me a link to a Continental document for the 85 that says I can put a 74 inch prop on my -85 and I'll start looking for one to buy tomorrow. I would love to have that extra 2.5 square feet of thrust area.
DC

[Guest]

Re: Adjusting Washout

Someone give me a link to a Continental document for the 85 that says I can put a 74 inch prop on my -85 and I'll start looking for one to buy tomorrow. I would love to have that extra 2.5 square feet of thrust area.
DC

Hi Darryl,

Airplane TCDS gives 72" and 71" max. for Sensenich and McCauley respectively but I bet you knew that.

McCauley TCDS for 1B90/1A90 gives that larger diameter IF the max. RPM is 2600 (look at the eighth line down).

See attached.

Dave

[astjp2]

Re: Adjusting Washout

McCauley 1A90/CF (seaplane only) 24 lb. (-32)
Diameter: not over 75 in., not under 73.5 in.
Static r.p.m. at maximum permissible throttle setting:
not over 2600, not under 2500

This is for the o-200, i am still looking for something with an 85 on it in seaplane configuration...Tim

For Model 8A seaplane with item 212 floats. Any 1A90-CF propeller which meets the
following limits:
Static r.p.m. at maximum permissible throttle setting:
not over 2170, not under 2070
No additional tolerance permitted.
Diameter: not over 74 in., not under 72.5 in.
(This propeller change dictated by undesirable vibrations in the static r.p.m. range with
the model 1A90-CF-7142. McCauley Service Bulletin No. 12, dated June 2, 1949,
covers the same subject).

[senior]

Re: Adjusting Washout

And


Really? 8-10 gal is 48 to 60 lbs. I didn't think the wheels weighed that much compared with skis. I pared my 46 BC12D down to a realistic minimum (albeit with skylight and the two wing tanks) and I came out at about 815 lbs empty.

My pre-war that I used to own (lighter than the post-war as we all know) was 777lbs empty of fuel.

Rob

Apoligies
After checkin my notes....
(I guess seniors shouldn't rely so much on memory!)
Weighed on the ice last winter (tail down) with scales, left-370lbs, right 390lbs, tail 82lbs =842lbs
Less fuel puts it right 800lbs or slightly less.

I still think 894 empty is heavy?
& a 70-40 prop seems like it would be spinnin it's wheels.

[flyguy]

Re: Adjusting Washout

Thanks guys for looking around for info on 74 inchers. Appreciate it.

Dave, thanks for the PDF. That is going to take some attention. I have to work out how that one ties in with the Taylorcraft specificatlions.

Have to check my prop today for sure. Think it is a 71 or 72, maybe about X46. This is not a high priority on my to-do list, but since I do mostly short local flights high cruise efficiency could be sacrificed a bit for a better climb rate.

All it takes is money, right?

Darryl

[Guest]

Re: Adjusting Washout

Yes for sure, merely money.

[Robert Lees]

Re: Adjusting Washout

Apoligies
After checkin my notes....
(I guess seniors shouldn't rely so much on memory!)
Weighed on the ice last winter (tail down) with scales, left-370lbs, right 390lbs, tail 82lbs =842lbs
Less fuel puts it right 800lbs or slightly less.

I still think 894 empty is heavy?
& a 70-40 prop seems like it would be spinnin it's wheels.

No apology necessary, Senior . Of course the weight is the same with a scale under each wheel in whatever attitude. 1 + 2 + 3 = weight.

The only reason to do the old "weights & measures" activity in a level attitude is to get the cg position.

800lbs +/- is about right, in my opinion, for a post-war BC2D.

As an aside, and for general interest only, there are fewer than 15 airworthy Taylorcraft in the UK. Some pre-war; some post-war and I have weighed most of them.
Only one came out as less than 780 lbs, and that was a pre-war with minimal equipment.

Rob