Engine Experts... C-85 Question

[astjp2]

Re: Engine Experts... C-85 Question

look at the seaplane prop approvals, they have a 75-35 1B90 that I know has been used on Tcrafts....Tim

[T-Rex]

Re: Engine Experts... C-85 Question

Does anybody know of somone who has goten approval to use a longer Mac1B90 on their C85 powerd plane. I would like to run a 74" 1B90, but I cant make the payperwork work out.

[Larry Lyons]

Re: Engine Experts... C-85 Question

Forrest
Which model electronic tach from HF? Some of their stuff works good, others don't and I could use an electronic tach for several things.


Randy

I am interested too as I have several other uses for a decent tach that did not cost me a first born! Larry
:joy:

[M Jones]

Re: Engine Experts... C-85 Question

Someone may be interested in trying out some free-ware that is suppose to measure engine RPM from the sound. It can be downloaded at the link below and installed on a laptop or pocket PC. A member/friend on this group sent it to me. I still haven't tried it out...

RPM From Sound

[rcefird]

Re: Engine Experts... C-85 Question

Forrest
Which model electronic tach from HF? Some of their stuff works good, others don't and I could use an electronic tach for several things.


Randy

[Forrest Barber]

Re: Engine Experts... C-85 Question

Pig in poop, now that is Happy! tie the tail to something or chock her.
Use a light , hanger or street or?? behind the prop late evening or night time, the blades will apprear to stop at multiples of 60 cycle/ sec. Like 1800 RPM & 2100 RPM. Quick easy check.
I now have an electronic tach from Harbor Freight that is very accurate.

[VictorBravo]

Re: Engine Experts... C-85 Question

I did my first test flight with the C-85 engine and the McCauley 74-47 prop yesterday instead of the 71-50 I had flown before.

Climb at 60-65 MPH was indicating 2150 RPM. Climb rate was quite good, no measurements taken.

Cruise at 2200 - 2250 RPM was 105 MPH IAS at 3000 feet.

No static full throttle RPM was observed because the brakes will not hold against full throttle.

Tachometer has not yet been checked for accuracy. That is the next little project.

Assuming that my tach checks out accurate and my ASI is not off, then I'm cruising at 22.8 miles per gallon at 4.6 GPH. Reducing RPM to 2000 gave me an IAS of 88-89, which the book says is 3.7 GPH, which gives me 24 MPG.

Right now I'm happier than a pig in poop

[Ragwing nut]

Re: Engine Experts... C-85 Question

Now I guess I'm confused. I was talking about the C85 vs. C90. Different cranks. Different cams, too, but I doubt if the cam has much bearing on vibration characteristics.

I stand by my original statement (for now). I know of no certified C85 installation with a McCauley 1A/B90 over 71 inches.

You quoted a reference to a Cessna so I thought you were referring to the differences between 90 and O-200. Nothing is the case is the same between 85 and 90 except gears and rear case.

[crispy critter]

Re: Engine Experts... C-85 Question

To continue off topic...

What is the certification basis for flying an o-200/c-90 in the a-696 airframe?

It seems to me that if the factory wanted to generate some business and goodwill there would be such an STC available. Didn't they demonstrate an LSA model that was o-200 powered, and couldn't the engineering data from that ship substantiate an STC?

Cheers
jCandlish
.

I have a one time STC for an 0200 on a short mount approved. Your welcome to have copies.

[astjp2]

Re: Engine Experts... C-85 Question

There is an STC already applied for.:hammer:

[jCandlish]

Re: Engine Experts... C-85 Question

I thought we were takling about a C85...

To continue off topic...

What is the certification basis for flying an o-200/c-90 in the a-696 airframe?

It seems to me that if the factory wanted to generate some business and goodwill there would be such an STC available. Didn't they demonstrate an LSA model that was o-200 powered, and couldn't the engineering data from that ship substantiate an STC?

Cheers
jCandlish
.

[NY86]

Re: Engine Experts... C-85 Question

cam is different, not the crankshaft. Only other major difference is the carb.

Now I guess I'm confused. I was talking about the C85 vs. C90. Different cranks. Different cams, too, but I doubt if the cam has much bearing on vibration characteristics.

I stand by my original statement (for now). I know of no certified C85 installation with a McCauley 1A/B90 over 71 inches.

[NY86]

Re: Engine Experts... C-85 Question

The C-150 had a 74+ inch seaplane prop approved on the O-200. Its a 1A90CF (seaplane only) not over 75 and not under 73.5, on page 4 of the TCDS

I thought we were takling about a C85...

[Ragwing nut]

Re: Engine Experts... C-85 Question

Wouldn't DREAM of it ! I appreciate your input.

My tachometer is somewhat suspect because there is a reversing adaptor on it. Meaning that I am using the same tach that the A-65 used, which I should not be able to do with an 85. I suspect that this was a common thing where people wanted to use the same tach as the previous 65HP engine used.

I will check the RPM's soon with some sort of an optical tack checker.

If the reversing adapter is 1:1, then it should be fine. However, I would have the tach checked just to be sure it is reading correct.

[Ragwing nut]

Re: Engine Experts... C-85 Question

Where do you find that? The only one I'm aware of is on the C90 where up to 73" is permitted. The C90 has a different crank and RPM limit, so vibration characteristics are different. AFAIK, there's no approved 1A90/1B90 installation on a C85 longer than 71".

The markings on the A65 tach will be wrong, but if you get it to turn the right way it should read right. Both are "1:1". Problem is most old tachs are really inaccurate.

cam is different, not the crankshaft. Only other major difference is the carb.