Hangar 9 1/4 Scale Cap Balance
03-17-2003, 05:18 PM
#1
Thread Starter
My Feedback: (21)
Join Date: Jul 2002
Location: Spencerport, NY
Posts: 7,350
Likes: 0
Received 0 Likes
on
0 Posts
Hangar 9 1/4 Scale Cap Balance
Between having the two elevator servos in the tail, and the lightweight OS 1.60FX engine up front, my Hangar 9 1/4 Scale Cap now appears to need 12oz of lead in the nose to balance it at the factory-prescribed location. With that much ballast, I'm looking at 13lb 8oz AUW.
How's that sound? Has anybody else had to ballast their H9 1/4 Scale Caps this much?
How's that sound? Has anybody else had to ballast their H9 1/4 Scale Caps this much?
03-19-2003, 03:49 PM
#3
Senior Member
My Feedback: (6)
Join Date: Feb 2002
Location: Ventnor,
NJ
Posts: 105
Likes: 0
Received 0 Likes
on
0 Posts
cap 232 balance point
I am not sure if you are talking about the 73" WS H9 Cap or the recent versions closer to 80" If the former, there has been a lot written on RCU about moving the CG back from 5-5/8 to 6-1/4 to 6-1/2. Do a search on "Cap snapping" and variations on "Cap 232" for all the information you could want.
Good Luck, Tim
Good Luck, Tim
03-19-2003, 04:32 PM
#4
Thread Starter
My Feedback: (21)
Join Date: Jul 2002
Location: Spencerport, NY
Posts: 7,350
Likes: 0
Received 0 Likes
on
0 Posts
Hangar 9 1/4 Scale Cap Balance
Yeah, I moved the elevator servos to about 12" forward of the rudder hinge line. I didn't like the original arrangement with the long pushrod runs. This way, I have nice short, stiff 4-40 pushrods, positive control, and the potential to have 45 degrees of throw.
I was expecting a weight closer to 12 pounds before adding ballast.
Once I get to trimming the plane out, I figure I'll probably end up removing some, or most of the ballast.
I was expecting a weight closer to 12 pounds before adding ballast.
Once I get to trimming the plane out, I figure I'll probably end up removing some, or most of the ballast.
03-30-2003, 08:42 AM
#5
Join Date: Jan 2002
Location: Centerville,
UT
Posts: 254
Likes: 0
Received 0 Likes
on
0 Posts
Hangar 9 1/4 Scale Cap Balance
I just finished mine tonight, maiden flight tomorrow. I have a ST G23 on the front, one hitec 645 for the elevator mounted in the stock location with a carbon fiber pushrod. Battery is mounted next to the firewall in the tank compartment. Mine balanced exactly at 5 5/8 from leading edge of the wing with no ballast. 12 pounds 4 oz dry. Putting the servos in the tail on this plane screws up your CG, as it is tail heavy to begin with.
05-26-2003, 01:23 PM
#6
My Feedback: (95)
Join Date: Aug 2002
Location: Mason, OH
Posts: 982
Likes: 0
Received 0 Likes
on
0 Posts
same prob
I had the same problem with my set up (h9 cap+2 rear servos+saito 1.80)
The saito is also a light engine. I had it balance with two 6oz sicks of lead.
What I ended up doing is moving my battery in front of my gas tank. I also added a 4oz header tank, so I can have 22oz of fuel for my saito to guzzle. With this configuration I added only 8oz of lead.
After flying this plane, I think about 5 7/8 to 6in would be good for a CG point.
Also I would like to add.... Last time I flew the cap I had uncontrolable fludder. I'm not talking about just the elevator, I'm talking the whole horizontal stabilizer. It was so loud and violent that it broke some hard wood in the tail of the fuselage.
I did recover the plane ok. Make sure all hinge gaps are covered and there is enough wood left for strength after you cut out the holes for the servos. If not your plane may go in on its first flight.
The saito is also a light engine. I had it balance with two 6oz sicks of lead.
What I ended up doing is moving my battery in front of my gas tank. I also added a 4oz header tank, so I can have 22oz of fuel for my saito to guzzle. With this configuration I added only 8oz of lead.
After flying this plane, I think about 5 7/8 to 6in would be good for a CG point.
Also I would like to add.... Last time I flew the cap I had uncontrolable fludder. I'm not talking about just the elevator, I'm talking the whole horizontal stabilizer. It was so loud and violent that it broke some hard wood in the tail of the fuselage.
I did recover the plane ok. Make sure all hinge gaps are covered and there is enough wood left for strength after you cut out the holes for the servos. If not your plane may go in on its first flight.
05-27-2003, 06:30 PM
#7
Senior Member
My Feedback: (15)
Join Date: Apr 2002
Location: Reston, VA
Posts: 310
Likes: 0
Received 0 Likes
on
0 Posts
Also same situation
Mine has servos in the stock location. I setup a pull-pull on the rudder to save weight and maintain good rudder performance. The engine is a Saito 180 with Slimline smoke pitts muffler.
I also have 2 6oz sticks of lead screwed to the front of the firewall. I also have a heavy 2400 mAh NiCad battery in front of the fuel tank. With all that I'm still toward the back of the recomended CG.
She's a little pitchy, most notable on landing. The plane also likes to tip stall on landing. I have to come in hot. Even flaring just 8" off the ground can result in one wing dropping like a rock. I went ahead and installed plastic skid plates under the wing tips.
Jason
I also have 2 6oz sticks of lead screwed to the front of the firewall. I also have a heavy 2400 mAh NiCad battery in front of the fuel tank. With all that I'm still toward the back of the recomended CG.
She's a little pitchy, most notable on landing. The plane also likes to tip stall on landing. I have to come in hot. Even flaring just 8" off the ground can result in one wing dropping like a rock. I went ahead and installed plastic skid plates under the wing tips.
Jason
05-28-2003, 01:58 AM
#8
Hangar 9 1/4 Scale Cap Balance
I had one of these planes. Lost it to a failed rudder servo.
I had a ST3000 up front and a total weight of 12 pounds dry.
I put my 2 elevator servos in the tank compartment. I routered two holes- one on each side of the fuselage- and mounted the servos to the tank floor. I had to buy 4-40 48" Sullivan semi-flexible rods. I had to put braces in the tail section to keep the rods from flexing. It worked- I got positive control throw and a light plane.
After installing the 2 elevator servos in the tank compartment- I sandwiched 2 1650 Mah 6Volt batteries up against the firewall.
I made a new tank floor to cover the servos and batteries. I put my tank on top of the new floor.
I had a ST3000 up front and a total weight of 12 pounds dry.
I put my 2 elevator servos in the tank compartment. I routered two holes- one on each side of the fuselage- and mounted the servos to the tank floor. I had to buy 4-40 48" Sullivan semi-flexible rods. I had to put braces in the tail section to keep the rods from flexing. It worked- I got positive control throw and a light plane.
After installing the 2 elevator servos in the tank compartment- I sandwiched 2 1650 Mah 6Volt batteries up against the firewall.
I made a new tank floor to cover the servos and batteries. I put my tank on top of the new floor.
05-28-2003, 02:01 AM
#9
Hangar 9 1/4 Scale Cap Balance
My elevator servos in the tank compartment. You can just barely see the servo horns sticking out and the control rods. Then I covered it all up with a balsa floor and mounted the tank over the top of it all.
The RX is between the elevator servos-- just behind the batteries. You can see the batteries on the firewall.
The RX is between the elevator servos-- just behind the batteries. You can see the batteries on the firewall.
06-03-2003, 02:11 AM
#11
Senior Member
My Feedback: (15)
Join Date: Apr 2002
Location: Reston, VA
Posts: 310
Likes: 0
Received 0 Likes
on
0 Posts
Hangar 9 1/4 Scale Cap Balance
By help, do you mean make it less likely or sudden? If so, the simple answer is no. An aft CG makes the plane more likely to stall at slow speeds because pitch is harder to control making it more likely that the angle of attack will exceed the stall point.
"Tip" stalling behavior is generally affected by three things:
* Total weight of the plane (lighter is better)
* Shape of the wing (any washout)
* Shape of the airfoil
As to not confuse, I won't edit the following paragraph, but my explanation of washout is bass ackwards
A wing that has some washout is less likely to stall suddenly because the wing is slightly washed out at the tips. That is, the ends of the wing have a slightly greater incidence than the root of the wing. Therefore, the whole wing doesn't stall at the same time. The outside of the wing stalls but the inside of the wing keeps generating some lift. The result is a stall the mushes instead of breaking suddenly (usually to one side).
Jason
"Tip" stalling behavior is generally affected by three things:
* Total weight of the plane (lighter is better)
* Shape of the wing (any washout)
* Shape of the airfoil
As to not confuse, I won't edit the following paragraph, but my explanation of washout is bass ackwards
A wing that has some washout is less likely to stall suddenly because the wing is slightly washed out at the tips. That is, the ends of the wing have a slightly greater incidence than the root of the wing. Therefore, the whole wing doesn't stall at the same time. The outside of the wing stalls but the inside of the wing keeps generating some lift. The result is a stall the mushes instead of breaking suddenly (usually to one side).
Jason
06-03-2003, 07:41 AM
#12
Senior Member
Join Date: Jan 2003
Location: Bristol, UNITED KINGDOM
Posts: 353
Likes: 0
Received 0 Likes
on
0 Posts
Hangar 9 1/4 Scale Cap Balance
Fishstyx - your definition of washout isnt quite right
Washout makes the tips have a reduced angle of attack thus the centre of the wing stalls first making the stall 'mushy'
You were describing washin - tips are at a greater angle of attack thus will stall first, making the aircraft drop a wing.
For aerobatics washout is a compromise - when inverted wash out will become washin, leading to tip stally behavour when inverted.
A better solution is to change the aerofoil shape at the tips. A blunter leading edge at the tips, and a sharper leading edge towards the centre will reduce the tendency to tip stall wether upright or inverted.
Washout makes the tips have a reduced angle of attack thus the centre of the wing stalls first making the stall 'mushy'
You were describing washin - tips are at a greater angle of attack thus will stall first, making the aircraft drop a wing.
For aerobatics washout is a compromise - when inverted wash out will become washin, leading to tip stally behavour when inverted.
A better solution is to change the aerofoil shape at the tips. A blunter leading edge at the tips, and a sharper leading edge towards the centre will reduce the tendency to tip stall wether upright or inverted.
