Hollmann HA-2M Sportster

Today I manufactured the pillow blocks that hold the control stick and the push rod driver bar. It came out pretty nicely! I painted everything white. Later this week, I will manufacture one more part of the mounting bracket, and then install the assembly into the gyrocopter. I need to order some pushrod ends from Aircraft Spruce, I shall do that this week.

I got an A on my Economics final! Yea… I learned that one hour working on the gyro provides more pleasure that one hour studying supply and demand charts. And I learned that working for 2 hours on the gyro provides twice as much fun as 1 hour does…

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I got the control stick mounted into the gyro today. Man what a tight fit… I had to trim a bit of aluminum off the lower rear of the cabin where the push rod driver bar passes through, that was sort of a pain in the ars…

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All I did today was weigh the aircraft, and bent the lower fire wall tabs back to required position.

Nose is 69 pounds, left and right mains are 45.5 and 46. Total weight 160.5 pounds.
 
Man that is a lot of work buddy, and you are doing an excellent job!
 
Today I ordered a custom 10" round by 23" long aluminum 7 gallon aux tank for the gyro from

http://www.coyote-gear.com

It will hang under the seat on the seat frame. This tank will weigh about 10 pounds, and has a sump so that I can get about 95% usable from it. I ordered the internal baffle, and it has a built in gauge that I will (just) be able to see down between the seats. I will install a 4 port, three tank fuel selector valve under the pilot seat right between the legs, below the seat lip. I have room to install a small panel there. If the pointer points left, left tank, center is center, and right is right. So I will have a max fuel load capacity of 21 gallons, provided I’m OK on weight and balance.

Because the tank is suspended from the seat frame, I was able to relocate the front seat supports to create a very nice triangle / truss support for the front outer corners of the seat tanks. I’ll post photos later. By relocating the forward seat support struts, the total load is better distributed to the center lower and diagonal keels, and the load now has 4 main anchor bolts as opposed to only two.

Soon I will get the seats bolted down, and I need to manufacture my harness attach points supports.
 
This is a Coyote Tank
 

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Today I pop riveted the lower aluminum aft cockpit skin into position, and fabricated the seat support bracket. I also painted the seat support bracket. I ordered my seat-belts, and harnesses from ASSC. Now I need to figure out the best place to secure them to the fuselage. I have a pretty good place in mind, but will need to fabricate some 4130 angel brackets to serve as an anchor point.
 
OMG, my stomach hurts from laughing so hard. :)
 
I trimmed the seat support struts down to final size so the seats will sit flat. As I examined the new seat support bar, I realized that it will hit the flight control systems during part of its movement, which is actually not a big deal, I was originally going to locate it at a different point, so now I will locate it there anyway. I was trying to make it a bit simpler by placing the struts between two points that already exist. Well, now I remember, it's faster to do it the hard way first. I also want to add some steel gussets at a few locations on the seat frame to better manage the weight load of the fuel tank seats, aux fuel tank, and passengers. all loaded up, there will be up to 530 pounds supported on the seat frame. I will also add two additional 18” long seat support rods. I'm lucky that I can easy add support and small gussets with very little weight penalty.

I bent the aluminum rods for my flight stick today, and will get those mounted tomorrow.
 
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Today I fabricated two seat supports out of my old seat supports and secured them to the mid-point where the weight of the seats will bear on the outer seat frame. I like this placement much, much better. I measured, and measured and measured, and measured; then, I drilled out the passenger seat bolt holes in the seat frame. Next I will manufacturer some small spacer blocks that will go beneath the seat frame. These blocks will allow me to use longer mounting bolts on the seats. Without the spacer blocks, the mounting bolts are up inside a very difficult to reach area (especially when the belly skin is on). I figure that someday, I’ll need to remove the seats for inspection and maintenance, and I will need to access the seat mounting bolts from inside the cockpit, by reaching around, and down under the seats, all the way back near the firewall. I could use a helper monkey, but I don’t have one. So, spacer blocks and longer bolts will allow the bolt heads to be #1 easy to find, and #2 easy to put a wrench on.

I should have my harness tomorrow or Saturday, and then I can scratch me head and install those angel brackets. I like angel brackets… sure, some people like angle iron, but I prefer angel brackets.

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PS I have decided that I will manufacture some 1” wide, 4130 steel support bars that will reinforce the end 3” of the seat frames, and bridge over a couple of spots. I just want the peace of mind to know that IF a crack should develop at the aluminum strut ends, the steel will carry the load and reinforce the seat frame ends. There will be approximately 530 pounds distributed over the seat frames, and I am just willing to pay the weight penalty, ( about ¾ of a pound) to have 4130 steel reinforcing on the seat frame ends.

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I measured and drilled out the pilot seat mounting holes in the seat support frame. Then I fabricated the spacer blocks that go under the seat frame, which allow the use of longer bolts. By using longer bolts, I can reach them from the inside of the gyro by standing on my head. If I use my left hand, and twist counter-clockwise at a precise angel.

I’ve been thinking about making a maintenance access panel on both sides under the seat. Just large enough to get an arm into, then I could reach the tank sumps WAY easier during preflight. I could do that…

My seat-belts and harness arrived last night… cool!

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Getting into the cabin is like slipping into a 150HP Isotoner glove. It's a snug fit, but I can see that a 6' 3" or so man could get in... It would be snug!.

But at any rate, the seats don't actually get torqued down once I get to that point. You simply place a dab of blue Locktite on the threads and gently snug them down. You don't want to pull the molded in aluminum inserts out of the seats. There are 6 mounting points on each seat bottom, and 2 points on each back. Calumet states that 4 bolts on the bottom are the minimum hold down. I will use all 6, but realistically, I should never get this baby in negative G's where the power of 6 bolts is needed.
 
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I designed the layout of the fuel system. I think it's pretty standard and straight forward.

I may not need check valves in the system if the pumps have this feature built in. Check valves (of some sort) are an important part of a two pump delivery system; because, without them, gas (may) be pumped around in a circle and not correctly pressurize the separate branches of fuel system.

I was wondering about fuel a “return” system, but Ellison fuel injection systems Inc DOES NOT recommend them for aircraft applications, except as a last resort for vapor lock prone systems. They do recommend insulating your lines and locating the fuel pump near the tank, away from the engine. This prevents about 95% of vaporizing problems. That will be easy to do in my gyro. My fuel pump will be under the seat, and under the fuel tanks.

In my design, I have my seat tanks with ¼ ID gas line, and my Aux tank has 3/8. So I will have to have a reducer before the fuel selector valve. I have a 3 position 4 port selector valve. This valve has all ¼ ports. ¼ ID gas line provides ample size for a 150 HP engine. It’s not uncommon to see dirt track racing cars (midgets) with 5/16” ID line with 250HP engines. I can easily flow 30GPH thru a ¼ ID line, and I am not going more than about 6 feet from tanks to engine.

In my system, the left and right tanks are full gravity feed through the selector valve, gascolator and to the fuel pump. The center Aux tank will have about a 1 foot rise from the tank outlet up to the selector valve, but then it’s downhill to the gascolator, and electric fuel pump. So even the aux tank will naturally siphon once gas is in the line… naturally siphon down to the fuel pump. From the fuel pump, it will be about 2 to 3 feet rise up to the engine.

Also somewhere in here, I will have a pressure gauge probably on the manifold at the engine, and also a fuel flow sensor that will send my GPH data to the instrument panel.

The fuel line will be 98% aluminum tubing, but will have very small sections of flexible gas tubing to allow for flex and vibration damping. The flex sections will literally be less than ¼ gaps between the aluminum sections, to prevent collapse under suction. Fuel line collapse under suction is probably not likely, but I just don’t want to take the chance.

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Anybody have a ball park idea about what a typical power descent nose down angle is on a gyro? Like at 750FPM at a speed of like 70MPH. What would you expect the nose down angle to be? My gyro has a published nose down angle of about of about -5Deg at 1100pound at about 70 MPH in straight and level flight. But what would it be if you then descended at say 750FPM. What angle do you get when descending at 750FPM?

I ask because I’m working out my usable fuel levels in worse case situations, and so I want to position my gyro into that attitude, but want to know what descent attitude really is realistic. (I’m not a stunt pilot) I prefer a 500 FPM descent but could see descending at 750FPM in an emergency of some sort.

Would 17deg nose down be unrealistic?

What say you…
 
I'm so dumb I impress myself... The deck angle should not change during descent, unless airspeed increases. The gyro hangs below the wing... completely free to move around at will...duhhh...

At 90 MPH and a GW of 1100 LB the published pitch attitude is -7Deg nose down. The angle will basically remain at -7Deg nose down in descent or climb as long as weight remains at 1100LB and airspeed remains at 90.

At 1100LB and 60MPH I will have a -2Deg nose down

At 1100LB and 35MPH I will have a +9 Deg nose up attitude...

Pitch attitude, weight and airspeed is important to know!
 
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