In my honest opinion, high speed testing is a necessary part of any
experimental airplane experience. I battled several issues with my airplane,
and I found them by doing high speed testing. During this time, I was
constantly talking to John Shaefer, Brad Nichols and other friends about issues
and solutions... sometimes you HAVE TO reach out to your friends for help...
1. Engine Ignition: My Revmaster engine was driven by a Bendix DR3000 magneto.
I had a lot of trouble getting this magneto to work correctly so I sent it out
to Tulsa for overhaul and setting of the correct timing. The mag shop in Tulsa
suggested that I not use this magneto since it was no longer supported but that
they could go ahead and replace worn parts and return without certification. I
then made the decision to go full electronic with an SDS system from Canada.
That whole process of re-inventing the wheel took me several months of trial
and error... during my high-speed testing I was satisfied that this solution
was the correct solution, and it now powers my airplane. I will talk more about
this at our meeting.
2. Prop: When I purchased my engine, the previous owner threw in a new prop.
During testing I found that this prop would only give me 2800 Static RPM. I was
looking for 3100 to 3200 RPM. I thought that my issue was carburation and not
the prop. After several iterations of adjustments, needle changes and whatnot,
I decided to call John Shaefer. After listening to my frustration, he suggested
a change of prop and said that he had a 52X54 available. I purchased the prop
and that seems to have solved the RPM issue...
3.Brake Pedals: Testing, I found that the brake pedals were poorly designed and
bent under a heavy brake load. Upon braking, I found that instead of applying
pressure to the brake cylinder, the pedals would bend and not stop the
airplane. I had to redesign the pedals and after several iterations I found a
workable solution using aluminum channels instead of thick flat plates. I
purchased some used brake cylinders at an aircraft salvage yard in Dallas, I
also purchased an overhaul kit from Spruce. In spite of the overhaul kit
providing new internals, during testing, I found that the cylinders were
bleeding through internally and not applying sufficient hydraulic pressure to
stop the airplane. This issue almost cost me the airplane since it allowed me
to wonder off the runway and into the grass several times.
4. Baffles: I had heating issues with the rear cylinders showing very high
temperatures. I found that my baffles were not providing a tight pressure
boundary thus allowing cooling to escape through gaps and ill fitted silicone
seals. I just completed a complete overhaul of the baffles, and I seem to have
corrected the issues.
4. My Revmaster engine has an Aero Injector, and It took me several weeks to
get this injector dialed in properly where it would give me the RPM;s necessary
for flight. This carb was my first experience with injector style carbs and
setting it properly was a challenge. I purchased several injector needles to
experiment with and still could not get it to run correctly. Part of the
problem that I found during my trouble shooting and calibration was that during
my engine assembly, I had been interrupted by a visitor at a crucial moment of
assembly. I found the right intake manifold loose. The engine was sucking air
through a gap caused by my mistake. I could not get the engine to idle
correctly and spent many days disassembling and re-assembling a carb that in
reality was working correctly. Once I fixed the problem the engine purred like
a kitten.
I wanted to enumerate all of these issues to show that when you think you are
finished and ready to take to the air, it is wise to spend time on the ground
running your engine and other systems to ensure that your aircraft is really
ready to fly. There are many instances that I can think of, that if I would
have taken off with one or more of these issues, I would not have had a very
pleasant outcome. Additionally, I did not bow to the pressures of my local
friends and visitors... I worked till I felt that I got it right. I now have 7
hours on the airplane and trying to fly every day to get this puppy ready for
Mt Vernon.
Presently I am doing time trials to get my airspeeds calibrated and practicing
fuel transfers since I am planning on flying non-stop to Mt Vernon. I want to
make sure I can transfer fuel from my aux tanks to the main header tank with no
issues. I am pressed against the clock but weather permitting, I will finish my
hours and aim the nose East...More to come...
Luis R Claudio
On Saturday, August 10, 2024 at 07:33:51 AM CDT, Larry Flesner via KRnet
<krnet@list.krnet.org> wrote:
On 8/10/2024 6:22 AM, n357cj via KRnet wrote:
> I had originally built a snorkle for the fresh air to carb and it was
> not the right thing to do but only became know by high speed taxing.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Joe,
When is that project going to fly? Most netters probably don't know the
story on your project, how different it is, how long ago it was
started? Web site? Photos?
More info on your carb issue on 357CJ ( that Langford now owns). What
was it and why didn't it work.
Anyone with valid engine testing procedures that work, share so others
can learn.
This whole thread started with the lesson learned (repeated) "don't use
plastic brake line all the way to the brake puck" and "carry a fire
extinguisher". Plastic line could be an issue on first taxi or 20
years and 1000 hours later. I hope that lesson has not been lost in the
shuffle.
How many days till Mt.Vernon????????????
Larry Flesner
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