Balsa USA enforcer
06-21-2004, 03:33 PM
#151
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RE: Balsa USA enforcer
Hi guys,
Let me make a few comments on the fuel line size with the OS .91 VRDF engine. I have been flying ducted fans with this engine for over ten years and have listened to a lot of opinions as well as seen a few results. My first comment is to use as large a fuel line as possible. I realize you can blow or suck a reasonable amount of fuel through a standard fuel line. However, the most critical time in the life of a model is when the engine is at idle, or throttling up from a long idle. It was suggested a long time ago to use nothing but 1/8" I.d. fuel line on the OS.91. This gives minimum resistance to flow at all settings. I have gone to 1/8" I.D. brass tubing in the tanks and drill out the clunks to fit them. Also, I/8" silicon tubing on everything else. For what it's worth, BVM recommends a hard, large ID, tubing for the pressure line for the reasons listed below.
The other concern is the size of the pressure line from the pipe. It should also be large ID for the same reasons. The other concern with the pressure line is how quickly the carb sees the pressure change due to a throttle change. If you throttle up quickly and the pressure line is too small, it takes time to pressurize a nearly empty tank due to the large air volume. It will also not allow the same tank to vent back into the pipe in a sudden power reduction, so all of the tank pressure is still forcing fuel into the carb even though you are now at idle. Think about it.
One thing is for sure. If you can't get the engine to go rich at full throttle, the fuel line/s is too small.
Joe
Let me make a few comments on the fuel line size with the OS .91 VRDF engine. I have been flying ducted fans with this engine for over ten years and have listened to a lot of opinions as well as seen a few results. My first comment is to use as large a fuel line as possible. I realize you can blow or suck a reasonable amount of fuel through a standard fuel line. However, the most critical time in the life of a model is when the engine is at idle, or throttling up from a long idle. It was suggested a long time ago to use nothing but 1/8" I.d. fuel line on the OS.91. This gives minimum resistance to flow at all settings. I have gone to 1/8" I.D. brass tubing in the tanks and drill out the clunks to fit them. Also, I/8" silicon tubing on everything else. For what it's worth, BVM recommends a hard, large ID, tubing for the pressure line for the reasons listed below.
The other concern is the size of the pressure line from the pipe. It should also be large ID for the same reasons. The other concern with the pressure line is how quickly the carb sees the pressure change due to a throttle change. If you throttle up quickly and the pressure line is too small, it takes time to pressurize a nearly empty tank due to the large air volume. It will also not allow the same tank to vent back into the pipe in a sudden power reduction, so all of the tank pressure is still forcing fuel into the carb even though you are now at idle. Think about it.
One thing is for sure. If you can't get the engine to go rich at full throttle, the fuel line/s is too small.
Joe
06-21-2004, 11:18 PM
#152
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RE: Balsa USA enforcer
Here is a plane that I built that is simular to the Enforcer
Its called a Clymax Delta, RCM plan 1142
I am now working on another Laddie M design called the Arrow RCM plan 1335, check out the progress at
http://www.rcuniverse.com/forum/m_15...tm.htm#1553735
SGG
Its called a Clymax Delta, RCM plan 1142
I am now working on another Laddie M design called the Arrow RCM plan 1335, check out the progress at
http://www.rcuniverse.com/forum/m_15...tm.htm#1553735
SGG
06-23-2004, 06:42 AM
#155
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RE: Balsa USA enforcer
Air brakes!!
I do the shaping durring the final sanding, if I were to have shaped the leading edges they would be dinged and dented and I'd have to fix them. Anything that gets messed up now will be gone with the final sanding.
I do the shaping durring the final sanding, if I were to have shaped the leading edges they would be dinged and dented and I'd have to fix them. Anything that gets messed up now will be gone with the final sanding.
06-23-2004, 07:20 AM
#156
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RE: Balsa USA enforcer
What i am looking forward to is a break down of the covering especialy over the wing with piccys (any takers guys) Im dreading the propellor slot. And as the body has so many curves ill spray mine after some kind of sealant is applied and sanded back. The problem here is of course is finding paint that matches the film colour.
I just aint gonna try n wrap film round that fuzz [
]
I just aint gonna try n wrap film round that fuzz [
]
06-23-2004, 11:04 AM
#157
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RE: Balsa USA enforcer
I didn't have too much trouble covering the slot. Just start with the smallet pieces of covering first, specifically fold some 1/4 inch strips longways and iron them on along the inside corners. You want a good seal there because that is where all the engine oil collects.
Speaking of the slot, don't use it as a handy place to pick up your plane when you do a power check. I lost an inch of my pinky a couple of months ago with that stupid move.
Speaking of the slot, don't use it as a handy place to pick up your plane when you do a power check. I lost an inch of my pinky a couple of months ago with that stupid move.
06-23-2004, 01:33 PM
#158
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RE: Balsa USA enforcer
I once saw a dog put its nose in the prop of a trainer and cut it clean off and was lying on the ground as the dog bolted while yelping. As to the prop slot ill make sure its well fuel proofed inside before any film is put on.
06-28-2004, 09:55 PM
#160
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RE: Balsa USA enforcer
The A-4 is a byron fiberglass airframe with built up wings, it was mostly built when I picked it up and no I don't have any plans or instructions for it.
WE don't need any stickin instructions
I'll go to work on it one day if I ever get a work bench cleared of.
WE don't need any stickin instructions
I'll go to work on it one day if I ever get a work bench cleared of.
06-29-2004, 01:18 AM
#161
RE: Balsa USA enforcer
Hey guys here is my progress so far, kind of slow on the building but is getting there.
I have the fan positioned at the location where it will go I'm trying to keep it closed to the CG to get a good balance at the end, also you can see the shape of the fuse. in front of the fan for better air flow and the fuse. has moved forward about two inches it will be glued to the wing after the wing gets sheeted, the retracts will come soon.
CARS II
I have the fan positioned at the location where it will go I'm trying to keep it closed to the CG to get a good balance at the end, also you can see the shape of the fuse. in front of the fan for better air flow and the fuse. has moved forward about two inches it will be glued to the wing after the wing gets sheeted, the retracts will come soon.
CARS II
06-29-2004, 02:11 AM
#171
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RE: Balsa USA enforcer
You folks in the US have it easy ....gallon of gas here is nearly £4.80 ..thas around 3 to 4 times the price.
Ill never own a dragster []
Ill never own a dragster [
]
06-29-2004, 06:07 AM
#172
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RE: Balsa USA enforcer
Cars II,
What fan is that? It looks like a JHH fan. And what engine? This is the first post I have seen on this particular plane.
I would highly recommend that you add light ply doublers to the wing ribs where the fan mounts attach. At least on the opposite side of the ribs, full height and for about four inches past the ends of the fan mount. You will be seeing a lot of stress on the mount as you start the engine, as well as some pretty good loads on the mounting ribs if the airframe ever comes to a sudden stop ( and sooner or later, that will probably happen-not neccessarly in a crash).
Good luck.
Joe
What fan is that? It looks like a JHH fan. And what engine? This is the first post I have seen on this particular plane.
I would highly recommend that you add light ply doublers to the wing ribs where the fan mounts attach. At least on the opposite side of the ribs, full height and for about four inches past the ends of the fan mount. You will be seeing a lot of stress on the mount as you start the engine, as well as some pretty good loads on the mounting ribs if the airframe ever comes to a sudden stop ( and sooner or later, that will probably happen-not neccessarly in a crash).
Good luck.
Joe
07-01-2004, 12:25 AM
#173
RE: Balsa USA enforcer
Dash, You are right it is a JHH Turbax/K&B 7.5 combo, this engine will be hard to find now days, I have a new one as a back up engine.
I totally agree with you on the reinforcement, that is what I will be doing this weekend, I will be adding two half light ply ribs, 1/4'' bass wood rails and will doubling ribs #2.
I have some experience with a Balsa nova that I did some time ago.
I will be posting pictures of it after it is done, any subjestions will be apreciated
CARS II
I totally agree with you on the reinforcement, that is what I will be doing this weekend, I will be adding two half light ply ribs, 1/4'' bass wood rails and will doubling ribs #2.
I have some experience with a Balsa nova that I did some time ago.
I will be posting pictures of it after it is done, any subjestions will be apreciated
CARS II
