[grosbeak]

Ignition cutoff enabled - here you can see the exterior red LED and the green LED on the cutoff transmitter module inside.




I also got the control servos set up - not really picture-worthy but direction, sub trim, end points, rates and expo are all set up.

I want to try the airbrake feature too... it will, of course, be tested three mistakes high... but I wasn't sure what to do with the elevator. I guessed that with the ailerons at the back of the wing and behind the CG, deploying the airbrakes would tend to raise the nose, so I added a little down elevator to counteract that. They're set to come on gradually so as to avoid sudden attitude changes.

Thoughts?

[grosbeak]

Nice day to fire up the engine for the first time (first time for me - I bought it used). Tethered on the table outside.




Like my DLE 20 and RCGF 32, this DLE 30 does not want to flip-start cold - I left the windshield off so I could see the tank and it's just not drawing fuel with hand flips. But the drill did a fine job as usual.



There was an issue with delayed idle so I cracked the low end open a tiny bit. That solved the problem.

- - -

So, you may ask, why didn't you just take it to the field, start it, tune it and fly it?

My usual answer is that I like to tune my engines at home. It doesn't come naturally to me and I like to take my time and follow a set procedure. For any plane that I'm starting for the first time I also like to see if any problems make themselves apparent, and in this case there were 3 of them.

To start with, there was some oil spatter on the table. I expect that, but I also noticed that there was some spatter on the firewall and the top of the muffler. Looks like I need to check out the seal between the engine and muffler.




The other two were inside. The first thing I noticed as I was packing the plane up was that the pull-pull cables for the rudder were slack. What the?! I looked inside and the arm was off the servo... looks like I forgot to reinstall the screw!

The second issue was with the receiver - it had slipped out from under the velcro tie. Both issues are fixed now.

Either of the latter two issues may have proven fatal to plane if they had happened in flight... so it only reinforces my habit of test running the engine of any new plane at home first.

[Mike Sebastien]

Why are you running a 3 bladed propeller? It will not pull as well as a 2 bladed prop.

A suggestion: As you fly the airplane gradually remove a piece of your nose weight and see how the airplane fly's. If it becomes sensitive on the elevator you can adjust with expo or replace the weights. It is always fun to experiment with a airplane and see what it will do or not do, you learn alot from that.

[grosbeak]

Originally Posted by Mike Sebastien

Why are you running a 3 bladed propeller? It will not pull as well as a 2 bladed prop.

A suggestion: As you fly the airplane gradually remove a piece of your nose weight and see how the airplane fly's. If it becomes sensitive on the elevator you can adjust with expo or replace the weights. It is always fun to experiment with a airplane and see what it will do or not do, you learn alot from that.

Hey Mike,

I'm not concerned with pull - the DLE 30 is more than enough engine for this plane. A 3-blade my give me better braking in the air, definitely gives more ground clearance, and looks much cooler.

I hear you on the CG experience - I did a lot of that with my 50cc SBach to get it just the way I wanted. With this one I'm looking for stable flight at cruising speed... we'll see if I need to add, remove or keep it the same for that.

Just a couple more things to take care of - I'm hoping for good weather this weekend or next.

[grosbeak]

The maiden flight was yesterday. The best way to summarize it is, "All's well that ends well."

The plane taxied well and responded well to rudder-controlled steering on the ground. In position facing into a mild headwind it took off in 50 to 75 feet at about half throttle in a nice level attitude - just floated off the ground.

In the air, things started to get hairy. When banking for the first turn, the low rates I had selected based on the manual didn't give me enough aileron authority... so I switched to high rate. The tail tended to drop - a lot - in turns. And even though the plane is perfectly balanced according to spec it flew like it was tail-heavy. I was flying a downwind leg on the third circuit working on the trim with a buddy at about 3 mistakes high when a small shiny object detached itself from the front of the plane - the spinner. As high as it was I decided to bring the plane in - on the crosswind leg there was a change in the engine note - a kind of rattling started. And on final, still descending and going too fast, the engine quit and I saw that the prop had gone too.

I ran out of runway but managed to set it down in the muddy outfield in one piece - from what I can see there is no damage to the airframe (that's the "ends well" part but I will be going over it thoroughly). But the single bolt prop adapter I had installed on this engine sheared all four of its bolts and disappeared. We walked the field but did not find it.





This is not the first time I've used a single bolt prop adapter - there's one on the RCGF 32 that powers my Pulse 125 - it's had a few flights and has been fine.

So now I've got to wonder - was the adapter, purchased new from Valley View RC - defective? Or was the engine - purchased used here on RC Canada - involved in a crash that may have bent the crankshaft? I take full responsibility - caveat emptor and all that - but I have contacted the seller with the question, which I should have asked before I bought the engine. I'm hoping for an honest answer but if the response is "no crash" than I'll have to decide whether to take that on faith.

In the meantime I think I'll check the runout on the prop hub with a dial indicator. We'll see what, if anything, that reveals.

If I'm being honest myself, I should have seen this coming. When I test-ran the engine on the plane the weekend before this, I could see vibration in the prop arc. I thought at the time it was just due to the vibration of the plane at idle but I've since realized that I've never seen wobble like that in an idling engine before. Live and learn.

[AESOP]

Originally Posted by grosbeak

Time to fuelproof the firewall. Instead of thinned or heated epoxy I went for Minwax Helmsman Spar Urethane (oil-based, not water-based).




I sanded the firewall with 220 grit before and between the three coats.



It brushes on easily, cleans up with Acetone and the smell is minimal, though I shut off the furnace before the application and left it off for several hours afterwards.

This tiny 236 mL can could probably three-coat more firewalls than I could build or assemble in a lifetime.

I need to Fire proof my Firewall on my PT60 Build...Can I buy the remaining from you?

[AESOP]

Sorry..meant Fuel Proof not Fire proof..lol

[grosbeak]

Originally Posted by AESOP

Sorry..meant Fuel Proof not Fire proof..lol

Thanks for the offer but I think we'll have other uses for it around the house - but you can find it at Home Hardware for $12.49.

[grosbeak]

I am not a machinist or engineer, but this - 0.004" - looks to me like a bent crank.

https://youtu.be/nYN0fx3IRV4

[JoeT]

That's the wrong way to measure crank runout. What you're measuring can be potential machining tolerance of the hub.

The correct way would be to remove the actual hub and measure the crank directly.