WACO YMF
08-02-2011, 05:29 PM
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RE: WACO YMF
Williec30
I calculated the balance point using a mean cord of 12.75 in. I used a dropline (line with a weight attached)
from the frt LE to the rear of the bottom TE, than blocked the plane up so tail would be level or 1/4 bubble
positive as I remember the plans call for 1 1/2 * pos. I than measured 4 1/2 inches from LE of top wing back,
lifted the plane & it remained in the same position "good" but plane weighs now 10.6 LBS a bit porky for a
1/6 scale. The wing loading has to be high?
I have a 90 OS surpass for power which seems to pull it right along no problems there. Last summer I flew it without incident but noticed the elevator was trimmed with down after landing. I than read parts of
the thread about it being tail heavy & procceded to add 1LB 6oz of lead in between the motor mount beams.
The plane is second hand, seems to nicely constructed but covered with solartex & than painted. Someone
at the field said to stripp of the covering lighten the tail & recover with monocoat., The way I had been flying
it must have been tail heavy as it did tip stall once & went into a downward spin. Trying to sort this all out.
Thank You,
Kim
I calculated the balance point using a mean cord of 12.75 in. I used a dropline (line with a weight attached)
from the frt LE to the rear of the bottom TE, than blocked the plane up so tail would be level or 1/4 bubble
positive as I remember the plans call for 1 1/2 * pos. I than measured 4 1/2 inches from LE of top wing back,
lifted the plane & it remained in the same position "good" but plane weighs now 10.6 LBS a bit porky for a
1/6 scale. The wing loading has to be high?
I have a 90 OS surpass for power which seems to pull it right along no problems there. Last summer I flew it without incident but noticed the elevator was trimmed with down after landing. I than read parts of
the thread about it being tail heavy & procceded to add 1LB 6oz of lead in between the motor mount beams.
The plane is second hand, seems to nicely constructed but covered with solartex & than painted. Someone
at the field said to stripp of the covering lighten the tail & recover with monocoat., The way I had been flying
it must have been tail heavy as it did tip stall once & went into a downward spin. Trying to sort this all out.
Thank You,
Kim
08-02-2011, 10:05 PM
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RE: WACO YMF
Kim,
Leave the covering alone. The Solartex is a whole lot better looking than $$-kote (who wants an plastic looking scale fabric airplane anyhow?)
10-1/2 lbs is not too bad for the 1/6 Waco. I will agree it is a bit porky but should be all right.
28% on a 12.75 chord is 3.57" not 4.5" (which is about 35% or 4.46"). 4.5" back is where the CG is called out on the original Platt Plans. I don't know what you can do to lighten the tail (change the tail wheel unit to something lighter?) with out some surgery. You may try moving the engine forward a bit (with out looking too far out of place) along with the balance weight to shift the CG forward. I will assume any radio gear is as far forward as practical.
Level the plane first and then recheck your drop line measurements. You should need to move the CG forward at least 1/2" (from the plans CG) to get in the ball park depending on what you come up with after the plane is level.
A Waco Y/UMF properly trimmed flies tail high as in P-1 below. 1987 YMF NC 14081
Leave the covering alone. The Solartex is a whole lot better looking than $$-kote (who wants an plastic looking scale fabric airplane anyhow?)
10-1/2 lbs is not too bad for the 1/6 Waco. I will agree it is a bit porky but should be all right.
28% on a 12.75 chord is 3.57" not 4.5" (which is about 35% or 4.46"). 4.5" back is where the CG is called out on the original Platt Plans. I don't know what you can do to lighten the tail (change the tail wheel unit to something lighter?) with out some surgery. You may try moving the engine forward a bit (with out looking too far out of place) along with the balance weight to shift the CG forward. I will assume any radio gear is as far forward as practical.
Level the plane first and then recheck your drop line measurements. You should need to move the CG forward at least 1/2" (from the plans CG) to get in the ball park depending on what you come up with after the plane is level.
A Waco Y/UMF properly trimmed flies tail high as in P-1 below. 1987 YMF NC 14081
08-03-2011, 05:45 AM
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RE: WACO YMF
Try using a wieghted spinner nut, placing the wieght as far forward as possible, means less wieght overall. By using a Harry Higley wieghted spinner nut I only needed 2 more ounces on the firewall on my 1/5 scale. It also looks more scale than the stock engine prop nut on the front.
Larry
WB 183
Larry
WB 183
08-03-2011, 06:28 AM
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RE: WACO YMF
"A Waco Y/UMF properly trimmed flies tail high "
Think of the flight of an arrow. The tail feathers will determine it's attitude. The horizontal stab will fly level to the direction of flight.
Les
Think of the flight of an arrow. The tail feathers will determine it's attitude. The horizontal stab will fly level to the direction of flight.
Les
08-03-2011, 07:15 AM
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RE: WACO YMF
jn4dflyer
Larry - Nice job on replicating NC 14031 with the cream, red trim and blue. Now you need to get a dummy engine in there to complete the look (Continental of course). NC 14031 has a Jacobs cowl over a Continental engine as it currently sits.
From the pictures and corospondence with Hank, the owner/restorer, the Blue is a lot darker. Hank thinks he used SIG insignia blue mixed with Diana Cream to do a good job matching to an original Berry Brothers color card; may have been 3 parts blue and one part cream. (he moved and can't lay his fingers on the exact formula right now). The original factory color was Berry Bros. Insignia Blue according to the original factory build sheet. The red was Berry Red (Tennesee Red a good match) and the cream appears to be Diana Cream. The interior was two different shades of red fabricoid but is currently done in Blue leather as indicated by the Paul Matt drawings. Hank purchased the leather before he had the factory build sheets. Paul Matt indicated the color of the interior as blue leather, which adds to a number of errors in his drawings and data, including reference to Navy blue vs. insignia blue.
Again, nice job
Larry - Nice job on replicating NC 14031 with the cream, red trim and blue. Now you need to get a dummy engine in there to complete the look (Continental of course). NC 14031 has a Jacobs cowl over a Continental engine as it currently sits.
From the pictures and corospondence with Hank, the owner/restorer, the Blue is a lot darker. Hank thinks he used SIG insignia blue mixed with Diana Cream to do a good job matching to an original Berry Brothers color card; may have been 3 parts blue and one part cream. (he moved and can't lay his fingers on the exact formula right now). The original factory color was Berry Bros. Insignia Blue according to the original factory build sheet. The red was Berry Red (Tennesee Red a good match) and the cream appears to be Diana Cream. The interior was two different shades of red fabricoid but is currently done in Blue leather as indicated by the Paul Matt drawings. Hank purchased the leather before he had the factory build sheets. Paul Matt indicated the color of the interior as blue leather, which adds to a number of errors in his drawings and data, including reference to Navy blue vs. insignia blue.
Again, nice job
08-03-2011, 09:18 AM
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RE: WACO YMF
OK will leave covering alone for now, was thinking of moving engine forward, but can only gain about 3/8 of an inch.
I also considered cutting off wooden mounts & installing after market nylon ones, but I don't know if firewall is strong
enough, was considering epoxing a new firewall over the existing one?? Have already changed the tail wheel. Also
though of removing covering from tail feathers & cutting lightening holes in the balsa... than recover with solartex
I also considered cutting off wooden mounts & installing after market nylon ones, but I don't know if firewall is strong
enough, was considering epoxing a new firewall over the existing one?? Have already changed the tail wheel. Also
though of removing covering from tail feathers & cutting lightening holes in the balsa... than recover with solartex
08-03-2011, 10:17 AM
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RE: WACO YMF
Kim,
Cutting holes in the tail area won't help much for the effort, I would leave it alone (getting a good match on the color would be a problem). If you were doing during the build, then yes, I would cut the holes or do a laminated frame instead of sheet with ribs. Add a dummy engine, the resin cast type are usually heavier and may help eliminate a solid chuck of ballast. I would mount the dummy to the motor mounts and not the cowl. Move the engine forward a little, a 1/4" can help a lot. Can you mount your batteries in front of the firewall? Have you flown the Waco after any of the mods?
Cutting holes in the tail area won't help much for the effort, I would leave it alone (getting a good match on the color would be a problem). If you were doing during the build, then yes, I would cut the holes or do a laminated frame instead of sheet with ribs. Add a dummy engine, the resin cast type are usually heavier and may help eliminate a solid chuck of ballast. I would mount the dummy to the motor mounts and not the cowl. Move the engine forward a little, a 1/4" can help a lot. Can you mount your batteries in front of the firewall? Have you flown the Waco after any of the mods?
08-04-2011, 03:31 AM
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RE: WACO YMF
Sky
Went back & blocked up plane & remeasured with weighted drop line... 15 3/4 in. balance pt now at 4.41 in. (28%) I now recall I had gone
through this excersize last winter, this is when I added another 1.6 lbs finally got it to balance at aproximately 4 3/8 in. I had mentioned this to
a buddy at the field & thats when he cautioned me about the weight & wing loading, telling me to lighten the tail to try & remove some of the
weight from the frt. also moving the engine foreward which I kinda figured. I guess at this time I should try & calculate the wing loading. The plane flew
very well on low rates before, but was very touchy on Hi rates...I figured it was just a little tail heavy, which it was. Do you know how to calculate the wing
loading? I might feel more comfortable knowing what it is. The highest I have flow is about 29, which is on a PT-19. I have noticed that the descent is quite rapid
with a dead stick.
Thanks ,
Kim
I still plan to move the engine foreward, move battery, get a heavy spinner hub as suggested & possibly a dummy engine than maybe I can remove some of the lead on the firewall
Went back & blocked up plane & remeasured with weighted drop line... 15 3/4 in. balance pt now at 4.41 in. (28%) I now recall I had gone
through this excersize last winter, this is when I added another 1.6 lbs finally got it to balance at aproximately 4 3/8 in. I had mentioned this to
a buddy at the field & thats when he cautioned me about the weight & wing loading, telling me to lighten the tail to try & remove some of the
weight from the frt. also moving the engine foreward which I kinda figured. I guess at this time I should try & calculate the wing loading. The plane flew
very well on low rates before, but was very touchy on Hi rates...I figured it was just a little tail heavy, which it was. Do you know how to calculate the wing
loading? I might feel more comfortable knowing what it is. The highest I have flow is about 29, which is on a PT-19. I have noticed that the descent is quite rapid
with a dead stick.
Thanks ,
Kim
I still plan to move the engine foreward, move battery, get a heavy spinner hub as suggested & possibly a dummy engine than maybe I can remove some of the lead on the firewall
08-04-2011, 07:45 AM
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RE: WACO YMF
Ok all you overachiever's. I'm running a 26cc engine with a 17x8 prop. I am getting 8 pounds ofthrust at max rpm of 7200. Mfg say's top rpm of 8000.
I tried a 18x6 this morning and lost thrust. Which way do I go with the prop to get more thrust, without loading up the engine of course.
I tried a 18x6 this morning and lost thrust. Which way do I go with the prop to get more thrust, without loading up the engine of course.
08-04-2011, 08:07 AM
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RE: WACO YMF
Robert for what it's worth I have always used a16/8 on all my 26's including my pica waco . I use an apc prop witch isn't scale or a laminated wood prop with good results
Jacque Waco Brotherhood # 27
Jacque Waco Brotherhood # 27
08-04-2011, 08:20 AM
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RE: WACO YMF
Robert, I don't know which 26 you have.
I have a G26, on ignition, in a Rascal 110 (13 1/2 lbs) swings an APC 18/6 wide blade at 8500. More than adequate power.
Lower pitch will give more initial thrust. Like gears in your car, low gear lots of pull, no speed, high gear lots of speed, but slower to get there.
Cheers,
Dave.
W/B #180
I have a G26, on ignition, in a Rascal 110 (13 1/2 lbs) swings an APC 18/6 wide blade at 8500. More than adequate power.
Lower pitch will give more initial thrust. Like gears in your car, low gear lots of pull, no speed, high gear lots of speed, but slower to get there.
Cheers,
Dave.
W/B #180
08-04-2011, 08:22 AM
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RE: WACO YMF
ORIGINAL: skylarkmk1
Kim,
I believe it is total square inches of wing area divided by weight (in oz.) or the other way around (weight/area).
Kim,
I believe it is total square inches of wing area divided by weight (in oz.) or the other way around (weight/area).
Just put the weight in oz (ounces of weight) and the area in square feet.
Make the division (weight / area )
Zor
08-04-2011, 08:27 AM
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RE: WACO YMF
Im running a rcgf supposedly a little more horse a little less rpm than the g. What I'm looking for is less speed more power. I fly the Waco at less than half throttle, now anyways. Would like a little more pull for the up side of the loop. Don't get me wrong she flies great as is, just want to slow it down and have more butt.
08-04-2011, 10:10 AM
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RE: WACO YMF
ORIGINAL: acerc
Im running a rcgf supposedly a little more horse a little less rpm than the g. What I'm looking for is less speed more power. I fly the Waco at less than half throttle, now anyways. Would like a little more pull for the up side of the loop. Don't get me wrong she flies great as is, just want to slow it down and have more butt.
Im running a rcgf supposedly a little more horse a little less rpm than the g. What I'm looking for is less speed more power. I fly the Waco at less than half throttle, now anyways. Would like a little more pull for the up side of the loop. Don't get me wrong she flies great as is, just want to slow it down and have more butt.
Regards
Michael
08-04-2011, 11:07 AM
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RE: WACO YMF
Michael, that's what I thought so this morning I tried a friends 18/6 and actually lost almost half a pound of thrust. What say you maybe 17/6.
08-04-2011, 11:08 AM
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RE: WACO YMF
Jim, it was a 18/6. With a 17/8 I get 8lbs thrust and this morning with the 18/6 only got 7.5 so I'm lost. My way of thinking went out the window with that one.
08-04-2011, 12:00 PM
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RE: WACO YMF
Robert,
To use someone else's analogy, you down-shifted and increased the wheel size. Stay with the 17” and decrease the pitch one step at a time until you get the power you want.
jimm
To use someone else's analogy, you down-shifted and increased the wheel size. Stay with the 17” and decrease the pitch one step at a time until you get the power you want.
jimm
08-04-2011, 12:12 PM
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RE: WACO YMF
ORIGINAL: n6iap
Robert,
To use someone else's analogy, you down-shifted and increased the wheel size. Stay with the 17” and decrease the pitch one step at a time until you get the power you want.
jimm
Robert,
To use someone else's analogy, you down-shifted and increased the wheel size. Stay with the 17” and decrease the pitch one step at a time until you get the power you want.
jimm
I started out with a 17x10 APC with an Aerovate 26cc. Too fast and not enough pull on the vertical. Been flying with a 17x8. It does fine but still would like a little more pull on the vertical. Gonna try a 17x6 when I get around to it. I know it's gonna slow down some, but that's ok as long as it's not too much and it doesn't rev too high.
Regards
Michael
08-04-2011, 12:14 PM
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RE: WACO YMF
ORIGINAL: n6iap
Robert,
To use someone else's analogy, you down-shifted and increased the wheel size. Stay with the 17” and decrease the pitch one step at a time until you get the power you want.
jimm
Robert,
To use someone else's analogy, you down-shifted and increased the wheel size. Stay with the 17” and decrease the pitch one step at a time until you get the power you want.
jimm
I started out with a 17x10 APC on an Aerovate 26cc. Too fast and not enough pull on the vertical. Been flying with a 17x8. It does fine but still would like a little more pull on the vertical. Gonna try a 17x6 when I get around to it. I know it's gonna slow down some, but that's ok as long as it's not too much and it doesn't rev too high.
And I wouldn't worry too much about the static thrust. See how it flies. But that's just me...
Regards
Michael
08-04-2011, 12:35 PM
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RE: WACO YMF
Thank's guy's for helping out with my brain fart. I will get back to it next week with a 17/6 or even a17/4 as suggested till it get's to where I want it.. Going off for the weekend.
08-04-2011, 12:50 PM
RE: WACO YMF
Robert,
I wouldn’t laugh at ya LOL
Thought Id post an update on the wing tips. Coming along great as you can see my trash pile but I do have another test in the making. One thing or another I don’t like about what I’ve done so far I’ll keep at it until I get it right or as right as I can.
I wouldn’t laugh at ya LOL
Thought Id post an update on the wing tips. Coming along great as you can see my trash pile but I do have another test in the making. One thing or another I don’t like about what I’ve done so far I’ll keep at it until I get it right or as right as I can.