vertical grimmace

My Feedback: (1)

Chris,
Looks like the temps are going to be down this weekend, so I will have to bring out a batch of green chili stew!

Oh, I went out yesterday and finally got some great flights on my Top flite FW 190. The retracts work great now. I had a cylinder leaking. A lot of bugs with that plane, but now it is slated to make the trip to the Nats in July. I plan to enter it in open. A static judged class with no builder of the model rule. So a refinished ARF is ok.

Joe-RCBuilder

Very nice! Good luck at the Nats.
Looking forward to the chili

Txmustangflyer

I'm sure there are others put there, that one was just what immediately came to mind.

Joe-RCBuilder

After a few attempts, I've determined a location for the pumps that meet the pump constraints and will also be inside the cowl. I put 40 more minutes of run time on the engines and they are running much better. The idle is not quite good enough, but it's getting there. I worked today to get the cowls to fit around the pumps, make the needle valves accessible, and put dummy engines in.

In the picts below you can see the pump location next to the carb and the cowling in place around it. Just dumb luck that the PBY had these large oil coolers on the side of the engine/cowl. Ended up being a place where the pumps could be.

Joe-RCBuilder

Well, the pumps helped. But they did not get the engines/plane to a place where it was ready to fly.

After more running and testing I decided to replace the fuel system. The engines really do not like working with the pumps. I did a test where I removed the pumps from the system. Note that the fuel tanks sit slightly above the engines when the plane is sitting on the ground, giving a gravity assist. In this configuration, then engines ran exceedingly well, better than with the pumps. Idle was reliable and the transition to full power was smooth. However, tipping the nose maybe 20 degrees up (tanks slightly low now) caused the engines to sag as the weak carb pumps could not overcome gravity. In this run, the needles were set slightly richer, again indicating that the pumps are forcing fuel past the needles. I backed the pump pressure off to as low as possible, but still could not get consistent results. Therefore, I pulled the current tanks, pumps, and lines out. Put in smaller tanks behind the engines and eliminate the pumps.

Let me be clear that the pumps DID work. The fuel was reliably delivered to the carb. But the Saito unique gas carb did not like having fuel delivered at pressure.

Here's the modified fuel setup. Tanks behind engines. Throttle servos moved to the firewall over the engine.
The engines run GREAT now.

Joe-RCBuilder

I have put 3 flights on the Cat now. It's been a bit of an experiment given the uncertainty with correct CG. I started with the CG at 30% and the plane was a bit of a "Wild Cat". It's been moved to 25% and she is much smoother to handle. With that CG she weighs in at just over 28 lbs. At 1/3 throttle it just cruises around the sky. Very stable in pitch. But I will say, that roll takes a bit more active management. There is no dihedral in the wing, so not a lot of tendency to roll level. It's not a big deal.

Here's a pict at the field. I'll try to get some video posted.
The landing lights are clearly visible in these picts and show up well in the air.

vertical grimmace

My Feedback: (1)

Great job! Congrats. I can't wait to see it in person.

Txmustangflyer

Glad you figured put the fuel. Awesome build.

vertical grimmace

My Feedback: (1)

It is like I always say, it is best to keep the tank as close to the carb as possible. Pumped or not.

mcmakin50

Very nice result!!

This build was impressively complex and I really enjoyed watching your build progress. Looking forward to the flight video.

John

Joe-RCBuilder

Thanks John. I see you are in Liverpool, NY. I was born there. I don't miss the winters. ... small world

Cati888

Love your Cat - just finished mine and waiting for better weather - see is electric powered 6s per motor

what did you set on your control surfaces much adverse yaw?

regards

Cati