A2A Comanche just become 5 mph faster

[Scott - A2A]

Just amazing. I've owned and operated this Comanche 250 since 2012, and it has always been about 5mph slower than it should be. There are so many things that can cause this both inside the engine to the airframe. Over the years, little by little, I have scoured and checked every inch of this airplane, including rigging measurements. The good news is through this long term frustration and unsatisfied curiosity I learned so much, so I'm actually grateful to have had this issue for so long.

Now my son Jake is using the airplane a lot for IFR training, and it's different maintaining an airplane for your son, rather than just yourself. IOW, I'm even more proactive in replacing components before they fail. Well, I replaced the carburetor (over 20 years old) and replaced the left side engine baffling. And guess what, we're 5mph faster....

Unfortunately I can't say exactly what the speed increase is from, just speculate. The carb definitely had some wear issues but leaking engine baffles are not only known for causing higher engine temps but reduce drag as it directs all the air out the appropriate channels.

The point I am proud of is, when we designed the AccuSim Comanche, I added about 5mph because that was my estimation of where it was supposed to be. And the other day I put the airplane through a performance test and it tested within +/- 1/2 mph of Accu-Sim.

It is SO GREAT to now be cruising so close to the yellow arc at 1900RPM and 25"

Scott

[DHenriques_]

Just amazing. I've owned and operated this Comanche 250 since 2012, and it has always been about 5mph slower than it should be. There are so many things that can cause this both inside the engine to the airframe. Over the years, little by little, I have scoured and checked every inch of this airplane, including rigging measurements. The good news is through this long term frustration and unsatisfied curiosity I learned so much, so I'm actually grateful to have had this issue for so long.

Now my son Jake is using the airplane a lot for IFR training, and it's different maintaining an airplane for your son, rather than just yourself. IOW, I'm even more proactive in replacing components before they fail. Well, I replaced the carburetor (over 20 years old) and replaced the left side engine baffling. And guess what, we're 5mph faster....

Unfortunately I can't say exactly what the speed increase is from, just speculate. The carb definitely had some wear issues but leaking engine baffles are not only known for causing higher engine temps but reduce drag as it directs all the air out the appropriate channels.

The point I am proud of is, when we designed the AccuSim Comanche, I added about 5mph because that was my estimation of where it was supposed to be. And the other day I put the airplane through a performance test and it tested within +/- 1/2 mph of Accu-Sim.

It is SO GREAT to now be cruising so close to the yellow arc at 1900RPM and 25"

Scott

Talk about a marketing tool ! Apparently we have now reached the point with Accusim where we are now using Accusim to make the real airplane more realistic.
Now THIS is what you call an A2A milestone.
!!!!!!!!!!!!!!!!!!!!!!
))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))

Dudley

[TreeTops]

This is what we love about A2A. Years down the track and you are still tweaking the plane to get it closer to the sim version.

[MarcE]

Replacing the carburator in my previous bike let the engine run a lot smoother and it drank significantly less.

[bladerunner900]

During my Starfire (BSA 250) rebuild many years ago, I re-ground the valves and cleaned the head. I cleaned all the carbon off, but in my enthusiasm, I ended up with a mirror finish on the head. My late brother had the same model but mine was always quicker and about 5 - 10 mph faster than his after that. Boy was I chuffed.

[Scott - A2A]

Replacing the carburator in my previous bike let the engine run a lot smoother and it drank significantly less.

Yes, I have also been able to run the airplane leaner with the new carb. I wonder if the newer carb is atomizing and delivering a smoother airflow as well, better distributing to the cylinders. Our Accu-Sim carburetor models this, as seen by being able to lean out fuel injectors more than the carb. But I can see an area where we can do this better.

BTW, saving 1gph over the engine life (2000 hrs) saves $9000 (at $4.50 ave fuel per gallon cost).

Scott.

[AKar]

I think this best shows how variable airplanes are from the next - even if here we are speaking of variations in the very same aircraft.

Even the latest high-tech fly-by-wire plastic electrotrickery thingies with more individual computers within than the entire STS programme and manufacturing tolerances of the arrows of the elves show differences in between them. And every individual build tends to vary over time, like Scott's Comanche apparently did.

At the other end of the spectrum, years ago as a young student gliding pilot flying my very first aerotows and thermals, I could easily tell and describe the difference in between two trainers of exact same make and model - and had my clear favorite that I thought flew better.

There are no two airplanes that are the same.

-Esa

[Hobart Escin]

Jake's new beard is obviously making him more aerodynamic.

[Jake - A2A]

Jake's new beard is obviously making him more aerodynamic.

Hahaha, unfortunately the beard left us on the 26th of last month!

[Lewis - A2A]

Hahaha, unfortunately the beard left us on the 26th of last month!

For shame Jake!

[EnDSchultz]

Hahaha, unfortunately the beard left us on the 26th of last month!

For shame Jake!

RIP A2A Accu-Beard(tm).

[Lewis - A2A]

Its OK there is still me and Mike carrying the Accu-Beard torch

thanks,
Lewis

[CodyValkyrie]

Simply wrapping the pipes on my motorcycle picked up a few extra horses. You’d be surprised how it all connects.

[Scott - A2A]

Simply wrapping the pipes on my motorcycle picked up a few extra horses. You’d be surprised how it all connects.

I wrapped the Comanche exhaust pipes a while ago and in just a short time they just disintegrated. How long did that wrap last?

[CodyValkyrie]

Simply wrapping the pipes on my motorcycle picked up a few extra horses. You’d be surprised how it all connects.

I wrapped the Comanche exhaust pipes a while ago and in just a short time they just disintegrated. How long did that wrap last?

It’s still going strong. Sort of. You have to get good wrap. There’s a lot of crap out there.