I myself thought about potentially using F33 or MZ34 but I wouldn't do it the way TEAM did, I would cut the nose shorter , make a flat square firewall and mount the engine with the rear spider mount , this would move the engine about 6 - 8 inches forward , finish it off with a nice small cowling. This pic is not the real thing but something like this to get the idea.
And worth noting . I would only use it on an airplane that is around part 103 - 250lbs territory, not one that is almost 100 lbs overweight.
The engine would have to move about 22 inches. And George is right about the gas tanks, I think that will likely force your hand to either get rid of the BRS or get a heavier engine.
This discussion is perfectly to the point for an existing aircraft but as someone who uses and teaches CG calculations and has for just about half a century now, I really want to emphasize that it makes a lot of sense to do your CG calculation BEFORE you build the aircraft. This is not hard as long as you are meticulous. All you have to do is do a spreadsheet listing the location relative to your chosen reference point and weight of everything which goes into the aircraft. This allows you to do your weight and balance calculation to a great degree of accuracy. Every stick of wood, every fitting, the cloth covering the surfaces, and the paint is carefully worked out. If you go into plenty of detail, you will be able to make your adjustments in the position of the engine, tanks, seating, etc. before you start construction and be quite sure that the final CG of the completed aircraft will be very close to your calculations. Generally it will be remarkably close as in a meticulous calculation the errors tend to not only be very small, but cancel out. This doesn't add anything that helps our fellow trying now to get his CG in the right range, but as a general recommendation for anyone starting a project it really is very useful.
I have a friend who owned a Belite ultralight with an F33 engine (legal ultralight in all respects). The plane was very underpowered to the point of dangerous to fly. It crashed twice due to stalling and spinning into the ground while in straight and level flight. The first time was while taking off....the pilot (CFI, many hours of experience, Airbus captain, etc) was making his first flight in the plane. He was aware of not climbing too steeply or too slowly, but the plane still stalled an spun in from about 100 feet. Pretty much totaled the plane but he walked away unhurt (except for his pride). He paid to have the Belite factory rebuild the plane.
The next crash was with the owner of the plane who had flown it several hours. On the first flight of the weekend he took off to the south. About a 1/2 mile south of the runway is a high voltage power line. He wasn't able to climb over the power line and had to fly under it. The crash was the next day....he was making a pass down the runway at 100 feet AGL and started to climb away. The plane stalled and spun a quarter turn before he recovered from the spin, but he was now flying into the top of a tree. The wing hit the tree and the plane fell straight down...again totally destroying the plane and putting the pilot in the hospital for many stitches.
You have a heavy aircraft. It cannot be made lighter with that specification and it is so far out of balance that it is not safe. There is only one answer and that is more power because just adding weight will make it less safe. You don't improve a heavy 'plane by adding ballast - quite the reverse. You need more power to drag it off the floor but with fifty horsepower (mine has 40 and cruises at 70MPH carrying 190lbs of me; It makes 800 FPM at 48 MPH, too.) you will have a LOT of bang for your buck. Buy a bigger motor. Carrol Shelby was right.
Trouble with relying on a nose tank for c.g. purposes is that the flight characteristics will change between full & empty tank. This in itself could be dangerous, if it means the plane flies differently depending on the amount of fuel you happen to be carrying. This is true to some extent no matter where your tanks are situated, but with wing tanks the c.g. hardly changes at all between full & empty, just the wing loading.
I resolved my aft c.g. problem by moving the engine forward, and adding a second battery in the nose. I reckon if you must carry ballast, at least make it useful: hence a battery rather than a lump of lead or iron.
Trouble with relying on a nose tank for c.g. purposes is that the flight characteristics will change between full & empty tank. This in itself could be dangerous, if it means the plane flies differently depending on the amount of fuel you happen to be carrying.
Bruce
The minimax was originally designed with the nose tank, the current 1100 plans show it with both wing and fuse tank options The 1030 plans are still drawn with only the fuse tank. If you believe this is troublesome and dangerous you should go and tell that to TEAM.
Bob you are right about 22" but I also need to carry fuel so more like 30" would be required It could be the first ever LongMax.
The only new piece of information I could gain by weighing it with fuel as it sits right now is the precise arm to use for calculating CG with different amounts of fuel. I will do that before it flies but for the sake of figuring out how to proceed math alone can get us close enough.
The CG for the tank should be pretty close to its center. That ends up being an arm of 55" from my datum.
An F23 is about 40lbs heavier than the F33. So doing nothing other than swapping out the engine the CG moves to 46.38" My range is 44.09 - 48.95, ideal CG is 47.87 So I can safely glide it in after consuming all the fuel.
Still including the engine swap: 5 gallons of fuel moves CG to 46.82 10 gallons of fuel moves CG to 47.22 13 gallons of fuel moves CG to 47.44 So still within CG range and pretty close to ideal when full of fuel.
Removing the F33 and installing an F23 really is the best solution here. I think I can handle making a new cowl, maybe even still get her in the air this year too.
You have a heavy aircraft. It cannot be made lighter with that specification and it is so far out of balance that it is not safe. There is only one answer and that is more power because just adding weight will make it less safe. You don't improve a heavy 'plane by adding ballast - quite the reverse. You need more power to drag it off the floor ....Buy a bigger motor. Carrol Shelby was right.
The minimax was originally designed with the nose tank, the current 1100 plans show it with both wing and fuse tank options The 1030 plans are still drawn with only the fuse tank. If you believe this is troublesome and dangerous you should go and tell that to TEAM.
If the CG is in limits with the nose tank empty the plane will be safe.
This discussion is perfectly to the point for an existing aircraft but as someone who uses and teaches CG calculations and has for just about half a century now, I really want to emphasize that it makes a lot of sense to do your CG calculation BEFORE you build the aircraft. This is not hard as long as you are meticulous. All you have to do is do a spreadsheet listing the location relative to your chosen reference point and weight of everything which goes into the aircraft. This allows you to do your weight and balance calculation to a great degree of accuracy. Every stick of wood, every fitting, the cloth covering the surfaces, and the paint is carefully worked out. If you go into plenty of detail, you will be able to make your adjustments in the position of the engine, tanks, seating, etc. before you start construction and be quite sure that the final CG of the completed aircraft will be very close to your calculations. Generally it will be remarkably close as in a meticulous calculation the errors tend to not only be very small, but cancel out. This doesn't add anything that helps our fellow trying now to get his CG in the right range, but as a general recommendation for anyone starting a project it really is very useful.
Tom
your post is very wise tom, that is how I built all my aircraft, models and full size. except the spreadsheet is my brain. I believe I can make my himax ultralight legal but that isn't my real goal. I want one gph fuel consumption at a modest 60 mph cruise.
C.G. to be moved forward. A piece of 2" foam, cut in the shape of the backrest and install as loose equipment. It moves body weight (your case 171 lbs) forward. Only adds a few ounces with out cover, more with cover. Purchase at local HD or from scrap shipping package. NOT bubble rap. BobN
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Remember if all fails you can always save it with this , One can solves any aircraft CG problem , use sparingly.
George, If that company makes an Anti-Gravity compound he could put that in the ass end and save weight and solve the cg problem at the same time. As a matter of fact I could use some of that on my own ass end. I wonder what 40 pounds worth would cost?
Can anybody explain how to get my bottle down from the hangar roof? 1GPH at 60 MPH. In a Himax? No. A fairly tidy 1600R with a 447 will fly at 55MPH on 2 GPH. That is with reflexed ailerons and a fully enclosed engine. You can get that down a bit with streamlined struts but a Himax is a little draggier than a mid wing.
I hesitated to reply because I didn't want to hijack ulbuilders thread, hoping he can find a solution to his problem. My skypup used 1 gph at 50 mph with a rotax 277. Empty weight 200 pounds. 170 pound pilot. NO windshield, high wing airplane similar to the minimax with bmx bicycle wheels and zero attempt at streamlining it. http://machnone.com/jeff.html
Can anybody explain how to get my bottle down from the hangar roof? 1GPH at 60 MPH. In a Himax? No. A fairly tidy 1600R with a 447 will fly at 55MPH on 2 GPH. That is with reflexed ailerons and a fully enclosed engine. You can get that down a bit with streamlined struts but a Himax is a little draggier than a mid wing.
1GPH at 60 MPH. In a Himax? Yes . With half VW . A clean light HiMax will need no more than 15 hp to cruise at 60. four strokes burn 0.7 gal per hour per HP , Half VW producing 15 hp will burn 1GPH. This is consistent with some people flying them reporting as their fuel burn.
Somebody - possibly Morry Hummel himself made some kind of record distance flight in Half VW MiniMax, I don't remember the details and cant find any reference , this was before internet.
Your Himax has a great deal of drag reduction equipment fitted and is not really representative, as you well know, George. Others have done the calculations for us and then Himaxhas is less slippery than a 1600r, due to the greater frontal area. The power increase required to get from 50 to 60 is considerable and from 60 to70, more so. The figures you quote I regard as completely believable because the way to make a Max of any description perform is to reduce drag.
Others have done the calculations for us and then Himax has is less slippery than a 1600r,
My real life experience shows the opposite, I actually drag raced against the TEAM factory Max103 when we were at similar configurations and I beat him, going about 70 mph at that time . This was before I made most of my cleaning modifications which gave me extra 10 and brought me up to 80. The cleanest MiniMax I was ever aware of was Klattman's Eros type but powered by 377, He claimed 80 mph top, I never got to fly next to him to verify it so I'm taking his word for it. I used mine and his as the two known best examples and calculated the flat plate drag area from known speed and power, The results were 1 less sq ft worth of drag in favor of the HiMax, from this then I constructed the table of speeds and fuel consumption of various configurations that can be seen on my HiMax page.
I attribute the better HiMax performance to the uninterrupted top of the wing surface which should give more lift with lower drag , while the MiniMax wing is passing through the the middle of the fuselage creating extra interference drag and even more as this whole junction also passes directly through the turbulent prop wash.
I concur with George that the additional interference drag of a mid-wing could easily give it more drag than either a high wing or low wing. Interference drag refers to the boundary layer on a wing or other appendage meeting the boundary layer of the surface it is attached to at an angle so that the two boundary layers "trip" each other and create a great deal of turbulence. This causes an enormous increase in drag. On a mid-wing with a non-filleted wing root there will be interference drag on the top of the root and on the bottom of the root. On a low wing or a high wing one side or another of this drag is eliminated.
Logged
I believe I can make my himax ultralight legal but that isn't my real goal. I want one gph fuel consumption at a modest 60 mph cruise. 
