Hollmann HA-2M Sportster

Way to go Cort!!!
 
I removed the nosecone today from the forms and let it bake in the sun. I also sanded a little bit here and there. It came out well all in all, and I am pleased with it.

I will still need to apply more poly-fill and then sand, prime, paint and clear coat… eventually...prime and paint will be just about the last step of the build.

I need to clean up and fill the edges of the part. I will also add in a couple of areas of reinforcing fiber to the inside of the part around the center section and around the landing light protrusion.

All in all I would say that I am 85% to 90% complete as far as weight is concerned on this part. It weighs in at a whopping 1.6 pounds! I have allocated 5 pounds for the nose cone, and really believe that I can get it right there at 2.0 to 2.5 pounds finished weight. Sweet! :yo:

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Looking good Cort!
 
Cort,

Vacuum bagging isn't too complicated. Main thing is to have a strong mold, so it wouldn't really work on your nose cone.

I make small fairings, trim that kind of thing with a ziplock bag and a small pump. It can be done with a modified cycle pump if you want to do it cheap.

I now use an old compressor from an aircon unit, it has way too much "suck" and have to be careful with it. A compressor from an old fridge will work too, or you can spend some of your hard earned cash on a dedicated vacuum pump. A vacuum cleaner would work too but it upsets the lady of the house usually.

This is great for NON STRUCTURAL items and hobbies but anyone wanting to go into aircraft production should buy the real stuff.
 
I use the compressor from an old fridge for a vacuum pump.

I also have a small venturi-style vacuum generator . The amount of airflow thru the vacuum generator dictates the amount of vacuum pulled and I use the tank regulator for this.

Another trick to getting the fibers to lay flat and stay embedded is to use Dacron peel-ply instead of wax paper. But it won't leave a smooth finish, it will have to be sanded or filled. However if you are going to be adding another layer the peel ply will leave a nice fractured finish ready for the next layup without sanding.
 
Sanded and filled the edges of the nosecone. I also laid an inner ply to the center portion of the nose cone to stiffen it up in that area. Then I resanded the edges where I laid in chopped carbon fiber. I applied flox into the inside of the landing light nacelle to fill out the sharp inner corners and provide additional strength to that area.

Flox is simply cotton dust mixed into the west system resin. It looks like and is the same consistence as cream of wheat, and you use it areas where you have tight inside corners as a fill where necessary. I just wanted extra strength inside the landing light nacelle.

Now I will apply more polyfill to the exterior of my part and resand. Polyfill is a two part epoxy that is really light weight and slightly fluffy. It works great to even things out as you build up fiberglass and carbon fiber things. It sands smooth like bondo auto body filler. In fact, it's called bondo for airplanes!

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And here we are after poly-fill was smeared all over. I will sand on Monday.

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I sanded the poly fill, primed and drilled out 4 mounting holes for the nose cone. I have a Friday appointment with Mr. Clinton Anderson in San Diego CA to weld up my control stick steel parts. Once all that is done I have aluminum parts to machine and finish on that assembly. After all that is installed, I can mount the seats into place, install seat belt mounts, and begin to wrap the bottom up. I actually am making pregress, but it sure is slow going. I think I like the look of the nosecone.

Now the difficult decision, what color scheme should I go with?

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Hi Cort,

Outstanding workmanship!

I've always liked the polished aluminum with the yellow nose cone, yellow trim on the vertical stabs and black "N" number that Martin eventually ended up with.

There are pictures of Martin's Sportster (N158) with Red vertical stab trim as opposed to the later yellow example. This color change perhaps correlates to the story I was told that N158 was involved in a crash at one of the Rockford Ill., PRA Fly-in and thus was rebuilt and the present color scheme added.

Cort, are you going to enclose the engine with a cowling like Martin did originally, or leave the engine area open as he later flew his example?

Wayne
 
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I was planing to enclose the engine area as close to the original design as I can, to reduce overall drag, like that matters much.

I was goofing off and made some comparisons between powered parachutes, gyro-copters and fixed wing light sport aircraft and made the following notes:

Powered Parachute
High wing
High drag wing
Fuselage independent from wing
55HP typical engine for a 2 seat aircraft
Glide ratio is about 4 to 1.
27 MPH forward speed
2.03 HP per MPH expended
Engine out straight down descent speed 600 to 750 Feet per minute (FPM)
42000 Feet per hour is 7.95 miles per hour at impact.
Straight down descent crash is easily survivable

Gyro-copter
High wing
Moderately high drag wing
Fuselage independent from wing
130HP engine typical for a 2 seat aircraft
Glide ratio is about 5 to 1
70 MPH forward speed
1.85 HP per MPH expended
Engine out straight down descent speed 1000 FPM (for the Hollman HA2M)
60000 Feet per hour is 11.36 miles per hour at impact
Straight down descent crash is easily survivable, but might hurt some.

Fixed wing
Low or high wing
Fuselage attached to wing
100 HP engine typical for 2 seat aircraft
Glide ratio of 16 to 1 or greater is typical
115 MPH forward speed typical
0.86 HP per MPH expended
Engine out straight down descent is not recommended, but could exceed 175MPH
16,600 feet per minute, is right at 1 million feet per hour or 189(ish) MPH.
Straight down descent crash is probably not at all survivable
I know, I know, a flat spin stalled FW will not descent at 189MPH, but will still kill you...


Analysis is that the gyrocopter is for all practical purposes a high performance powered parachute. A gyro-copter will descend straight down a little faster than a guy in a parachute.

Pretty cool...
 
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Officially I wasted about 75 hours building the full glass windscreen first, and then removing it and replacing it with my signature partial aluminum nose skin, and partial glass above the instrument panel. I'm glad I did it, but I wish I had done it that way in the 1st place...
 
ironcowboy : I started reading your thread today and I can tell you have a lot of time building. I think you are doing a good job and it looks great also!
 
Hay there Dirty Dog, I once lived in Sumter for quite a few years back in the 80's. I did a lot of dirt bike riding back then, good times, good time.
 
ironcowboy : Down here next to Savannah, GA and Hilton Head Island, SC Big city of Bluffton.
 
Well I spent 11 hours yesterday at Custom Aircraft Parts getting my flight control sticks and assembly built (welded).

Thank you All_in... AKA John Roundtree for recommending them, they are great folks, and keeping busy.

Anyway. If this large assembly looks a little weird to some of you it is because, on the HA2M there is a 12 gallon gas tank that mounts in the middle of this frame. I have opted to use seat tanks so this space can remain open, or I can put a small overnight bag tray there, or I can put a 6 gallon aux tank there...

I'm leaning to the aux tank, provided I can make my own tank out of fiberglass. By adding a 6 gallon aux tank, I can have 20 gallons on board fuel provided I'm OK on weight. At 7 GPH I can safely fly a 2.0(ish) and still have 30 min VFR reserve.

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PS. The sticks look short... above the steel, they turn into aluminum, and bend back and over the pilot's lap. The pilot flies from the left seat with the left hand, and guards the throttle or radio knobs with the right hand, like how you do it when crusin the hood, you always need your right hand free to shoot out the passenger side windows.

I don't advocate firing out of moving aircraft unless you have this endorsement on your license.
 
Yaw Mon my pleasure. They do excellent work and it looks good buddy!

11 hours, no wonder you did not come by to see our Hollmann!!
 
LOL, it was 5.5 hours of welding, and 6 hours of driving... I slept like a baby last night...


Now I need to plan a trip to inspect the your HA2M. :)

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