Back to Work

OK, dodged that bullet. Hurricane Ian turned south of Tampa and wiped-out Fort Myers area. Had it remained on track to hit Tampa I might be writing a different blog today. Instead, I watched a good bit of the blow outdoors in my hot tub. The biggest damaged I had was the wind blew my phone into the tub. Big deal. My friend in Ft Myers had a meter of water in his house. I had to rake up 4 bags of lawn debris and get a new phone.

Soon as I could I flew back to Dayton to get the Vtwin running and am staying here to get this work done and the two Merlins in our hangar much closer to flying. In fact, I am camping in our R&D garage. It is warmer than the hangar and I now my thick Wisconsin blood has been replaced with thin Florida blood. Or maybe I am just getting older.

Garage camping in Dayton.

So on to the real news: The Vtwin on the Merlin runs great! But we sure had some trials and tribulations to get there.

We are finishing two Merlins in parallel in our Dayton hangar. We started the Vtwin on Merlin #1 prior to the hurricane break. But it didn’t run as smooth as we expected. And it would not restart immediately after shutting down but needed a minute. We spent a lot of time trouble-shooting wiring harnesses and fuel pressures/flows with no joy. When we ran out of idears and the storm was imminent we planned to move to Merlin #2 Vtwin. This week we set it up for operation and using the same fuel pressures and flows and same wiring harness started it up. Or tried to. We had solenoid issues first. Then got a big back-fire for our efforts. The fix was simple. We reversed the fuel injector leads and tried again. Engine ran great! Finally. And here it is:

We ran the engine quite a bit. In the hangar with no prop, it did appear to get too hot, so we shut down and moved outdoors for testing with a big fan in front. That went very well. The thrust feels perfect. But I only had a hand tach to measure it with. You can see it in the video but note that it is measuring prop RPM. Divide by 2.23 to get engine RPM.

Although I put a pretty big bite of 20 degrees on the prop it still was not enough. I re-pitched to 25 degrees and ran it up. Felt like I was gonna pull the van we tied the Merlin too.

This result sure took a while but now we know our wiring harness is correct. Vtwin #1 must have a faulty sensor somewhere. We will get that sorted. Meanwhile we can move forward significantly.

First thing is to make a proper wiring diagram. This is done. See above. 2nd is to document the lengths, colors, and connectors. That will be done Monday. 3rd effort is to get this information to our engine manufacturer for production which we will do this coming week. And 4th step is to get a bunch made and sent out to our Vtwin customers along with the rest of the FF PKG parts.

It also means we can get on with the rest of the work to finish these Merlins so we know what exactly to ship to our customers and know that it is all correct. Now I am working on cowl installation, finishing the BRS, wiring the trims and strobes and fuel senders and antennas, and a dozen other tasks. But all manageable work. Our double E, builder Don, has a pile of work remaining. His remaining tasks:

  • Finish the engine wiring diagram documentation
  • Mount all the remote avionics on our new avionics tray
  • Design and build the avionics wiring harness
  • Cable up the 4 antennas
  • Finish the fuel control circuit board and program the automatic fuel management system
  • Order more avionics and fuel circuit boards and components and get them all populated
  • Program the EMS to monitor the Vtwin properly
  • Program the EFIS to match the Merlin performance

Side note: When we have the MGL panel programed all of the EFIS shipped and to be shipped will have this programming on a SD disk to upload into the unit.

Only then will we allow Don to get back to finishing his own Merlin. He has sacrificed a lot to get this Vtwin project done.

So, what about the rest of the parts? TPA has a long list and has been working very diligently to get everything manufactured and packed in the next container. We plan to ship around October 20th. The next 4 Merlin aircraft are about ready now, just getting final work done and all these parts finished.

Meanwhile, I can work on these two Merlins and get them ready for Don to complete the avionics installations then get the FAA to sign them off and we can finally fly!

Reader #13 noticed a new page on our web site:

I don’t know how it got there but apparently, we are offering another new Part 103 ultralight. But don’t worry, this is Francesco’s work. It will not slow down our Vtwin and Merlin Lite development or production. It does, however, expand our product line to include a very light ultralight that we could possibly develop 750 amphibious floats for. Plus, it has a 2-minute wing fold so this aircraft can fit on a boat lift or small boat trailer. No hangar needed. We plan to show this new aircraft at SNF next April.

Back to work,