ETLB Squawk Forums — Archive

A couple of pics:

looks good, can't wait to hear how she flies

WOW bob I love the look of that little plane, cant wait for a flight report.

Chris

Loved that breezy design you've got Bob.
Phil

This is what JDT could work on, a good looking variant of the minimax, a p-max (parasolmax)
Congrats for your bird ))))

Erkki

Looks nice.  I see you have two bracing wires going from the aft fuselage to the top of the cabane.  On an Airbike these wires go from the fuselage to the top of the rear wing struts.  This prevents any twisting of the wings in relationship to the fuselage.

The brace wires are drag wires (anti-anti-drag?).  I calculated a chordwise force of 600 lbs acting forward at point A of the flight envelope.  The cabane structure has to react this force.  The canted struts could take it in compression, loading the vertical struts similarly in tension.  I'm unsure of the strut attachment's ability to take the compression loads although I did test a sample to 500 lbs in tension without signs of failure.  The brace wires were simple to add and calculate the loads.  They also relieve some of the fuselage truss loads imposed by the tail down force at point A.  

At the moment, the asymetric loads you mention are resisted entirely by the vertical cabane strut pairs, the maximum load is in the front struts, 554 lbs.  The Airbike cabanes can't resist these loads very well.  The triangle formed by the struts is very acute and the struts are subjected to bending.  My struts form more nearly an equilateral triangle.  I suppose relocating the wires from the cabane out to the wing rear strut attachment would kill two birds with one stone. I'll give it some thought.

Congratulations! Nice job and of course ... One of a Kind  

Nice looking plane!!

Really love the looks of your parasol max! I hope to get back to my conversion soon. Job and location change this summer has everything on hold yet again. But your photos are inspiring! Great job! Can't wait to hear how it flies!

Bob,

I was just doing some research on your parasol max, did you ever get to fly her?

Chris

I was hoping to get her to the airport this year but had a health issue in August.  Since these photos were taken a w/b showed tail heavy with half fuel or less so I moved the engine forward on two u-channel rails. I also attempted to analyze the structure, after the fact, to confirm it was airworthy.  That resulted in a better anchoring of the cabane brace wires, some cleats around the cabane strut attachments and corner bracing of the fuselage at what was the front spar carry-through station. The engine was overhauled this year and I've been breaking it in.  I'm waiting on some coarser pitch blocks from Hoverhawk for the ultra prop. The Tennessee prop in the pictures isn't enough load for wot. I had been working on a glider rating but covid has shut that down. I feel confident that with a couple of hours of taxiing I will fly her next year.  The airport nearest me, beside class C Albany, has a hangar waiting but it shuts down November-May because it's turf and the owner doesn't plow it, not that I'd fly off ice and snow anyway.

Did this max used to be a standard one?  I can see the holes in the sides where it looks like the wings used to go?

my guess it was a minimax at some point. Looks like a fabulous Idea.

It was a standard 1100R with the "heavy tail".

Thanks for the update Bob! she sure looks nice!

Chris

Wait, so is there a kit I can buy to just... make my max into a himax? How hard was it to convert?  Your plane is incredible!

Yes, there are plans to do just that. Contact Team. I think they may even be on the website.  

I remember seeing their plans but they seemed to be more meant to be done while the plane was being built.  I've never seen one like Bob's.

The cabane structure is my own design.  It eliminates the center section on the Himax so I lost some span.  I'll have a higher wing loading and stall speed.  It could be lighter. The root tube interrupting the top surface of the wing is embarrassing and unnecessary.

Oh interesting..  Well, if you ever open up your plans or sell a kit, count me as interested!  You did fine work.

How do you get in and out of your bird?

Would adding a bay on each side help to regain the initial stallspeed?

Or would it be enough just to cover up the center section for flight?

Rgds from Switzerland

Erkki

The upper longeron is just low enough and I am just flexible enough to get a foot over it.  Then I pull my butt onto the longeron by the cabane tubes.  It isn't easy.  A step stool would help.  I haven't had the wings on long enough to experiment.  I intend to make a fairing  that wraps around the wing junction and seals the top of the wing as much as possible. My wing area is 107 ft² and my takeoff weight should be about 440 lbs.  Then stall speed should be about 32 mph.

Maybe you know it,  but definitely put the fairing on. Dont know where I read it, or the details of it, but someone tried flying without it on an Airbike and I guess it was a sketchy flight.

Flydog,
That was AirbikeAce, he had his skylight blow out of his fairing in flight. He had to take his shirt off and stuff it in the hole to seal it because he couldnt maintain altitude with a hole between the wings.

Chris

That's right Chris. Losing the little bit of lift the skylight/fairing provides is vastly destroyed by the air rushing up through that space and "spilling" lengthwise over a portion of the wing. It was a frightening experience and as Chris said, I poked my long sleeve shirt up into the skylight hole to plug it. That saved me from a forced landing. When I did land at an airport, I noticed that one of the long sleeves from my shirt was sticking out past the hole. To someone on the ground it must have looked like I was waving through the wing!

Paul Fiebich

How big is the hole created when the skylight fails?

Paul, does your wing fairing wrap completely around or is it primarily just the upper surface?  I intend to wrap about 80% including the entire flat bottom portion ahead of the ailerons.  I read your account of the inflight emergency, how much of the initial problem would you say was due to the drag and spoiler effect of the protruding window? How much due to the pressure losses? Thanks.