Sig Morrisey Bravo Build
12-16-2014, 03:53 PM
#76
Thread Starter
I'm glad you made it here Mike, welcome.
I remember looking at the plans for the first time, I saw something I didn't like, something that I wanted to change. That something was where the aileron servo was placed. The plans positioned the servo at the extreme end of the aileron, taking some initial measurements confirmed that I had the room to shift it over one bay. If you notice I even lengthened the servo leads tube over as well...it wasn't until today that I said to myself why shift it over one bay when I can shift it over two bays and have the servo actuate the aileron on its center. So poor planning on my part left me with the servo tube one bay short, but that didn't stop me from making the move.
I had made the servo cover and brackets previously, so tonight I glued it into position as you can see. Clamps ensured that everything was held into position as the glue dried. The cover was left 3/32" proud from the top of the rib so when the rest of the wing gets sheeted with 3/32" balsa it will be flush. The front end of the servo bracket is also anchored to one of the wing's spar for additional strength. Epoxy and additional blocking will ensure that nothing will move.
I remember looking at the plans for the first time, I saw something I didn't like, something that I wanted to change. That something was where the aileron servo was placed. The plans positioned the servo at the extreme end of the aileron, taking some initial measurements confirmed that I had the room to shift it over one bay. If you notice I even lengthened the servo leads tube over as well...it wasn't until today that I said to myself why shift it over one bay when I can shift it over two bays and have the servo actuate the aileron on its center. So poor planning on my part left me with the servo tube one bay short, but that didn't stop me from making the move.
I had made the servo cover and brackets previously, so tonight I glued it into position as you can see. Clamps ensured that everything was held into position as the glue dried. The cover was left 3/32" proud from the top of the rib so when the rest of the wing gets sheeted with 3/32" balsa it will be flush. The front end of the servo bracket is also anchored to one of the wing's spar for additional strength. Epoxy and additional blocking will ensure that nothing will move.
Last edited by VincentJ; 12-16-2014 at 05:01 PM.
12-17-2014, 03:54 AM
#78
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Maybe also to keep the wing tips light and weight close to CG. I imagine (newbie here) the servo's of that day were much bigger and heavier.
One thing I am learning with building functional models is, everything is a trade off.
The bigger the model the fewer the trade offs ( unless you mod the crap out of it) but still trade offs.
Press on Vince, love your builds
Kevin
One thing I am learning with building functional models is, everything is a trade off.
The bigger the model the fewer the trade offs ( unless you mod the crap out of it) but still trade offs.
Press on Vince, love your builds
Kevin
12-17-2014, 10:41 AM
#80
Thread Starter
If you mount the control horn on the end of the aileron as shown on the plans then the aileron will flex more due to the length. If you place the control horn in the center of the aileron it will be much more stable. I basically have split the length in half which will reduce flexing considerably.
12-17-2014, 10:43 AM
#81
12-17-2014, 10:52 AM
#82
I would guess the need would depend on what the load was on the aileron? For instance the LT40 has a aileron the length of the wings with one servo controlling both and works just fine. The Morrisey Bravo I would think would be a more acrobatic airplane with wider ailerons and would put more stress on the controlling servos?
12-17-2014, 10:52 AM
#83
Thread Starter
Exactly! If you mount the control horn on the end of the aileron as shown on the plans then the aileron will flex more due to the length. If you place the control horn in the center of the aileron it will be much more stable. I basically have split the length in half which will reduce flexing considerably.
12-17-2014, 05:17 PM
#85
Thread Starter
The only formula that I use is called LAR (looks about right). I think that if you center your control linkage on your control surface and make it 90 degrees from the trailing edge, that would give you optimum results...As I stated earlier , I'm no engineer and there's probably some study that someone has done that shows where the most critical stress points are on a wings control surface during flight. That point would probably be the best placement for the control horn.
Shown on the plan is where I intend on placing four hinges for each aileron. These areas will need additional blocking as I intend on using Robart hinges. You can also see that I freed the aileron from the wing using a blade that I removed from one of my Zona saws. With the aileron out of the way I set out to strengthen each area that would receive hinge points. Using 1/4" thick balsa, I cut each piece to fit in-between the top and bottom rear wing spars, doing this will add the strength that I'm looking for.
I think that if you center your control linkage on your control surface and make it 90 degrees from the trailing edge, that would give you optimum results...As I stated earlier , I'm no engineer and there's probably some study that someone has done that shows where the most critical stress points are on a wings control surface during flight. That point would probably be the best placement for the control horn.Shown on the plan is where I intend on placing four hinges for each aileron. These areas will need additional blocking as I intend on using Robart hinges. You can also see that I freed the aileron from the wing using a blade that I removed from one of my Zona saws. With the aileron out of the way I set out to strengthen each area that would receive hinge points. Using 1/4" thick balsa, I cut each piece to fit in-between the top and bottom rear wing spars, doing this will add the strength that I'm looking for.
Last edited by VincentJ; 12-18-2014 at 10:35 AM.
12-18-2014, 12:16 PM
#87
Typically air moves across the wing laterally starting at the leading root and ending at tip trailing edge and most of the turbulence is at the end of a aileron. That's part of the reason for turbulators out there to get more performance control through turbulence, the best example is war birds and their smaller area ailerons and elevators. One of the best places to put control horns on a tapered aileron is about one third of length of aileron measured from the inside, that will be at the point of equalized pressure across it for most applications
Vince you did some lateral bracing on your Edge ailerons to stiffen them up and at the same time sheeting them makes them pretty stiff, it's the open frame ones that need more attention.
Leroy
Vince you did some lateral bracing on your Edge ailerons to stiffen them up and at the same time sheeting them makes them pretty stiff, it's the open frame ones that need more attention.
Leroy
12-20-2014, 12:06 PM
#89
Thread Starter
OK, here's one for those of you that thought you've seen it all...as I started laying out the right wing half today, I thought I was having a bad day as I couldn't seem to get my measurements accurate. That is until I found out what was causing me grief. Today's lesson, go check your rulers boys.
Last edited by VincentJ; 12-21-2014 at 04:55 AM.
12-20-2014, 03:47 PM
#91
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That's a shame. General used to make a good product.
When working with another cabinet maker when cuts of multiples mater. Synchronizing tape measures is a good idea.
That little springy end of a tape gets tapped in or out till both tapes read the same. As long as the same standard is being applied.
The standard being nonstandard doesn't matter.
That first inch and last inch on cheaper rulers is usually plus or minus. If the middle ones are out, well. Time to buy a Starret.
Kevin
When working with another cabinet maker when cuts of multiples mater. Synchronizing tape measures is a good idea.
That little springy end of a tape gets tapped in or out till both tapes read the same. As long as the same standard is being applied.
The standard being nonstandard doesn't matter.
That first inch and last inch on cheaper rulers is usually plus or minus. If the middle ones are out, well. Time to buy a Starret.
Kevin
.
12-20-2014, 05:51 PM
#93
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Oh no !!!!!!!!!!!
Say it isn't sooooooooooooooooooooooo
.
I have a Starret combination square that I just love. (paid 90 smackers for it).
I know, I walked buy that square for years before I swallowed hard and bought it.
It is my favorite non power tool.
The rule slides like butter. All sides of the rule are machined perfectly square. Corners of rule finely broke. Fine finish. All increments finely etched and inked.
Thumb screw locks rule rigid without slop.
The body of the square is machined square on all edges. I set machines up with this square. It is dead on.
I'm shocked too Vince. Does everything have to go to poo ?
Kevin
Say it isn't sooooooooooooooooooooooo
.I have a Starret combination square that I just love. (paid 90 smackers for it).
I know, I walked buy that square for years before I swallowed hard and bought it.
It is my favorite non power tool.
The rule slides like butter. All sides of the rule are machined perfectly square. Corners of rule finely broke. Fine finish. All increments finely etched and inked.
Thumb screw locks rule rigid without slop.
The body of the square is machined square on all edges. I set machines up with this square. It is dead on.
I'm shocked too Vince. Does everything have to go to poo ?
Kevin
12-21-2014, 04:13 AM
#95
Thread Starter
Very funny Anthony, however inflation is supposed to take away, in this case it added! LOL
Leroy guess I never thought about a fake or knock off, you could be right, but it looks real to me...who knows! Maybe like misprinted coins this is worth something.
Kevin, like you I appreciate good tools and I love my square which I purchased many years ago from Snap-on tools, like yours it has given me many years of dependable accurate service.
On another note, I found this slip of paper in the bottom of my Bravo box. Loved the little touches that Sig did years ago! You did well Pauline, thank you!
Leroy guess I never thought about a fake or knock off, you could be right, but it looks real to me...who knows! Maybe like misprinted coins this is worth something.
Kevin, like you I appreciate good tools and I love my square which I purchased many years ago from Snap-on tools, like yours it has given me many years of dependable accurate service.
On another note, I found this slip of paper in the bottom of my Bravo box. Loved the little touches that Sig did years ago! You did well Pauline, thank you!
Last edited by VincentJ; 12-21-2014 at 04:53 AM.
12-21-2014, 11:53 AM
#97
Vincent, how did you determine which ruler was incorrect? What did you use for a standard?
I'm not doubting your work, I'm wanting to know what to use to check mine. I've worked with calibrated instruments most of my career, but have never came across the need to calibrate a ruler.
Thank you,
Glenn
I'm not doubting your work, I'm wanting to know what to use to check mine. I've worked with calibrated instruments most of my career, but have never came across the need to calibrate a ruler.
Thank you,
Glenn
12-22-2014, 03:29 AM
#98
Thread Starter
Very good question Glenn, when I found the discrepancy between the two rulers I was sure that the Starret was accurate and the other wouldn't be. I took another steel ruler and measured it against the Starret and it too was off but it was the same length as the first. I did this with about seven or eight rulers that I have and the only one that was off was the Starret!
12-22-2014, 04:00 AM
#99
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The only true way to know is, to take your ruler down the Bureau of Weights and Measures.
Ask them to go to the vault to get the Standard out so you can check your ruler.
The will bring out this shoe from the 18th century.
Kevin
Ask them to go to the vault to get the Standard out so you can check your ruler.
The will bring out this shoe from the 18th century.
Kevin
12-22-2014, 09:57 AM
#100
Thread Starter
With all of my Christmas shopping finally done I got a chance to spend some time in my workshop. Completed trimming out the new basement door and hung all of my stuff up on the new peg board. Even spent some time assembling the right wing half! If you note, I am in no hurry to trim off the ends of the spars, etc. on the ends of the wing. It will come out so much better if you let them run proud of the last rib, then sand them flush later...
