new project - is this stabilizer big enough? + photo's
06-17-2003, 07:57 PM
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new project - is this stabilizer big enough? + photo's
First of all: I have the tendency to make large posts, if you don't want to read it, plz comment on the pictures. I can use all the advice ...i have no club or commen flying place and i've been out of the hobby for 3 years...so i've got ALOT to say 
ELEKTRO UHU ex-glider fuselage next to OS .25FX + 9-6 graupner PROP
Fully movable scratch built 2 part stabilizer with lock mechanism wich i forgot to take a photo of.
it will probably have an inverted engine...good idea or will it give me problems????
I am working on a plane that consists of : crashed GRAUPNER ELEKTRO UHU fuselage, 110 cm flat bottom trainer wing with 10 cm dihedral, OS .25 FX, SRATCH built stabilizer (no hinging, f22 style) rest of tail section coming later.
One of the pictures shows me holding the OS where it probably will be when i cut the nose and install firewall....I plan on mounting it upside down (please say so if i shouldn't be doing that with that particular if any engine for some reason....tank positioning maybe??? the fusalage only caters for the tank to be in one place....the center so....)
The stabilizer is fully ribbed and sheeted with 2 mm balsa and is, considering the tools i have at disposal, a work of art
...the model will be used as: trainer (with the current wing...no ailerons. As i don't fly in a club, friends can easily be persuaded to become flying buddies, if you give em some airtime ), a hi speed demon (with a SIG DOUBLER .15 wing) and aerobatic plane (with scratch built high camber wing i plan too built)
my concern is that the stabilizer might be too small to be 3D(large throws)- or trainer(small throw) - suited.
SHould i built small wingtips????
i'm thinking sharkfin like ones that add about 3 maybe 4 cm the each side of the stabilizer
Hard part is to find the courage to start sanding AND to get it over my heart that i won't ever see the beautiful outer ribs...
ELEKTRO UHU ex-glider fuselage next to OS .25FX + 9-6 graupner PROP
Fully movable scratch built 2 part stabilizer with lock mechanism wich i forgot to take a photo of.
it will probably have an inverted engine...good idea or will it give me problems????
I am working on a plane that consists of : crashed GRAUPNER ELEKTRO UHU fuselage, 110 cm flat bottom trainer wing with 10 cm dihedral, OS .25 FX, SRATCH built stabilizer (no hinging, f22 style) rest of tail section coming later.
One of the pictures shows me holding the OS where it probably will be when i cut the nose and install firewall....I plan on mounting it upside down (please say so if i shouldn't be doing that with that particular if any engine for some reason....tank positioning maybe??? the fusalage only caters for the tank to be in one place....the center so....)
The stabilizer is fully ribbed and sheeted with 2 mm balsa and is, considering the tools i have at disposal, a work of art
...the model will be used as: trainer (with the current wing...no ailerons. As i don't fly in a club, friends can easily be persuaded to become flying buddies, if you give em some airtime
), a hi speed demon (with a SIG DOUBLER .15 wing) and aerobatic plane (with scratch built high camber wing i plan too built)my concern is that the stabilizer might be too small to be 3D(large throws)- or trainer(small throw) - suited.
SHould i built small wingtips????
i'm thinking sharkfin like ones that add about 3 maybe 4 cm the each side of the stabilizer
Hard part is to find the courage to start sanding AND to get it over my heart that i won't ever see the beautiful outer ribs...
06-18-2003, 12:08 AM
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new project - is this stabilizer big enough? + photo's
The horizontal stabilizer should be about 15 or 20 percent of the wing area of the main wing. That is a general rule. The rudder should be about 10 percent of the area of the main wing.
For best results with fuel the middle of the fuel tank should be at the same height as the needle valve of the carburator on the engine. That will allow easy flow of fuel to the engine when the fuel tank is full or near empty. If this is done then the engine will not have to work hard to get fuel.
I prefer to have the motor mounted upright bacause the motor gives me the least amount of problems that way. It idles well and accelerates easily with no tendency to stall out. However I have had good results by mounting the engine sideways. If the engine is mounted upside down you may find that it 'floods out' the glow plug during very low speeds for example when landing. And sometimes it is just a little more touchy to start because of fuel running down toward the hot glowplug and cooling it off. However you could try starting the engine with the plane upside down.
I suggest that you strengthen the center section of the wing with fiberglass cloth and epoxy. Do this before covering. The weight of the engine and the fuel can really put a load on the center of the wing when you take a tight turn at fast speed for example when you pull out of a dive. Use one piece or fiberglass on the top sheeting and one piece on the bottom sheeting. The cloth can be 4 inches wide. Center that on the center of the wing and work epoxy down into the cloth. Let it cure completely. You can use masking tape just outsid the edges on each side of the fiberglass cloth to make a nice clean lines ending to the epoxy you spread.
Make sure the wing is very securely mounted on the fuselage again because the weight of the engine and fuel fuel will try to make the fuselage pull away from the fuselage during a tight turn or at the end of a dive.
Fuel will try to get everywhere behind the engine. So try to make the plane as fuelproof as possible. The tail will generally get some fuel on it during a flight so make sure that area is protected. With the 'full flying stab' you have you will have to make sure you cover everything with covering material and coat any exposed wood with epoxy to make it fuel proof. If you use a muffler you can sometimes add a heat proof tube to the place where the fuel leaves the muffler and direct the fuel under the fuselage. That mey help keep the wing area dry and minimize the amount of fuel that gets on the stab.
Make sure the plane is balanced properly when you have everything completed. Balance it with NO fuel in the tank. This will make it a little mose heavy when you fill the fuel tank and balanced just right when the tank is empty.
Make sure the wing has a little washout at each wingtip to help prevent tip stall.
For best results with fuel the middle of the fuel tank should be at the same height as the needle valve of the carburator on the engine. That will allow easy flow of fuel to the engine when the fuel tank is full or near empty. If this is done then the engine will not have to work hard to get fuel.
I prefer to have the motor mounted upright bacause the motor gives me the least amount of problems that way. It idles well and accelerates easily with no tendency to stall out. However I have had good results by mounting the engine sideways. If the engine is mounted upside down you may find that it 'floods out' the glow plug during very low speeds for example when landing. And sometimes it is just a little more touchy to start because of fuel running down toward the hot glowplug and cooling it off. However you could try starting the engine with the plane upside down.
I suggest that you strengthen the center section of the wing with fiberglass cloth and epoxy. Do this before covering. The weight of the engine and the fuel can really put a load on the center of the wing when you take a tight turn at fast speed for example when you pull out of a dive. Use one piece or fiberglass on the top sheeting and one piece on the bottom sheeting. The cloth can be 4 inches wide. Center that on the center of the wing and work epoxy down into the cloth. Let it cure completely. You can use masking tape just outsid the edges on each side of the fiberglass cloth to make a nice clean lines ending to the epoxy you spread.
Make sure the wing is very securely mounted on the fuselage again because the weight of the engine and fuel fuel will try to make the fuselage pull away from the fuselage during a tight turn or at the end of a dive.
Fuel will try to get everywhere behind the engine. So try to make the plane as fuelproof as possible. The tail will generally get some fuel on it during a flight so make sure that area is protected. With the 'full flying stab' you have you will have to make sure you cover everything with covering material and coat any exposed wood with epoxy to make it fuel proof. If you use a muffler you can sometimes add a heat proof tube to the place where the fuel leaves the muffler and direct the fuel under the fuselage. That mey help keep the wing area dry and minimize the amount of fuel that gets on the stab.
Make sure the plane is balanced properly when you have everything completed. Balance it with NO fuel in the tank. This will make it a little mose heavy when you fill the fuel tank and balanced just right when the tank is empty.
Make sure the wing has a little washout at each wingtip to help prevent tip stall.
06-18-2003, 12:36 AM
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new project - is this stabilizer big enough? + photo's
the only way you can get away with a stab 15 percent the area of the wing is with a longer tail moment from what i have seen 3d type aircraft are short coupled and need the larger stab area.
06-18-2003, 11:44 AM
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new project - is this stabilizer big enough? + photo's
thanks Keith Johnson, for the big reply....i was gonna fibre glass the wing BUT i will probably mount the engine upside down. The landing gear would have to be to tall if the engine is placed upright without protruding the top of the fuselage...if i place it any higher the tank (wich i can not place diferently) will be to low
the stabilizer is about 25 percent of the wing 34 cm vs. 110 cm so i geuss it will work (maybe not for 3d, but that was an exageration to start with, seeing i have only flown an aileron type plane twice....not counting the endless simulator sessions)....so the only thing i want is to have both a trainer for newbie friends and a very sporty flying machine that is capable of short term hovers when the fully symmetrical wing is finished.
the stabilizer is about 25 percent of the wing 34 cm vs. 110 cm so i geuss it will work (maybe not for 3d, but that was an exageration to start with, seeing i have only flown an aileron type plane twice....not counting the endless simulator sessions)....so the only thing i want is to have both a trainer for newbie friends and a very sporty flying machine that is capable of short term hovers when the fully symmetrical wing is finished.
