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RE: WACO YMF - 5/7/2008 1:37:55 AM   
Stickbuilder



Posts: 5219
Joined: 11/20/2005
From: leesburg, FL, USA
Status: offline
quote:

ORIGINAL: Hughes500E

Hey guys,
First flight of the season last night with the Waco I thought I would share!

I did make a few changes over the winter, new under carriage, new aileron servos and Receiver etc etc. It was like maiden flying all over again

Once again the engine right thrust or lack of played into it rudder has a lot of trim. Offset that engine or vertical fin if you're building!
I went from a 16x8 prop to an 18x6 prop and the air frame didn't like it, lots of P factor. I thought I would throw that in for you guys considering gas.
The grand slam, after the third flight I decided to dial in some aileron differential. Not sure if we have talked about this on this thread yet but it is a must. I went for 50% down compared to up on both sides and it's a different aircraft. Flies like a big kite now, even the landing was easier )




We have talked about aileron differential several times. Personally, I use 30% down, as compared to up, and the lack of adverse yaw is just great.

What kind of RPM's are you getting out of your G-26 with the 18X6, and which prop were you using? I really need to know this, since this is the engine that I'm running on the new one.

Once again, I don't advocate any right or down thrust on any R/C model. I build mine straight up at zero/zero. That's what the rudder is for. Every Waco that I've ever flown used throttle management to change altitude, and the elevator controlled speed. I just think that these models look wierd with the prop hanging slunchwise out of the cowl. That's just my opinion, and it's served me well. Using the rudder all the time makes me a better flyer.

Bill, AMA 4720
WACO Brotherhood #1

_____________________________

It's easy, just glue all the pieces together, and sand off everything that doesn't look like an airplane.

(in reply to Hughes500E)
       Post #: 6226

RE: WACO YMF - 5/7/2008 1:39:00 AM   
Stickbuilder



Posts: 5219
Joined: 11/20/2005
From: leesburg, FL, USA
Status: offline
Okay, Here is the roster to date.

WACO BROTHERHOOD MEMBERSHIP:

#1 stickbuilder
#2 Hughes500
#3 Jim Henley
#4 mmattockx
#5 CTflyboy
#6 michaelj2k
#7 Ronj10
#8 gwulle
#9 jim schroer
#10 Skinny Bob
#11 Bart5495
#12 Pimmnz
#13 HarryJ
No. 14 Old Git
#15 ChrisMH
#16 Nerevar
#17 Ricatic
#18 Clay H.
#19 Tripp2Loo
#20 KHodges
#21 Bill Hogue (WACO One)
#22 Mangolo (Waldo)
#23 av8ter
#24 yel914 (Rick)
#25 damifino
#26 skylarkmk1
#27 Jacque
#28 Edwin
#29 AROPLANE
#30 CubNut (Anthony)
#31 BQuartucy (Bob Q)
#32 AERORON
#33 funkymusic
#34 Live Wire (Larry)
#35 obo (Bob)
#36 Jackk36 (Jack)
#37 fatherrooster (Jim)
#38 Ilikebipes
#39 Kestrel0222
#40 CROWMAN17 (Marc)
#41 redcesar
#42 S. Christensen (Scott)
#43 Bill Deidrich
#44 Mike Barbee
#45 mrdhud (Dan Hudson)
#46 SoCalSal
#47 Todd (NightStalker)
#48 argon (Bob Gonzalez)
#49 mango 12 (Scott)
#50 skyjet 1
#51 ZIG
#52 Didg
#53 MarvinE255 (DOC)
#54 Joe Norris (Full Scale WACO Pilot)
#55 vasek
#56 SuperCub Man (Jim)
#57 Black Drape (Ron)
#58 aminiet (Angel Minet)
#59 Snowball
#60 doc zinger
#61 jagnweiner (Scott)
#62 Meesh (Bob)
#63 BigBoy99 (Bernie)
#64 stifts (Steve)
#65 RCWalker (Wallace)
#66 Mobyal
#67 lazyace
#68 bladerunner1955 (Don)
#69 trlambsr
#70 Big Bird (Ken)
#71 Tony V (Tony)
#72 red 1
#73 412t1 (Sean)
#74 Mr Lucky (Ben Warner)
#75 RICKSTUBBZ (Rick Stubblefield)
#76 ffdg (Fred)
#77 tomcraig
#78 Michou41a Michel
#79 Watzscale (Dick Watz)
#80 Devens
#81 msilvestro (Mark)
#82 Cheechukranch (Lewis)
#83 kruzin55 (Chris)
#84 lynchr (Ron)
#85 airplanegeek
#86 Mainer Jim
#87 Garthwood (Charles)
#88 RCBOATMANIAC (Dave)
#89 Thomas B
#90 George Werber
#91 frequent flyer (Don)
#92 adamiani Axex
#93 Kvlasblom
#94 geertdewit (Geert)
#95 Wobble Wing (Bud Halverson)
#96 Joe Gulik
#97 T.L.A.R.eng
#100 nine o nine (Mitch Epstein)



WACO Sisterhood Roster:

S-1 Janelle (Lady Stickbuilder)
S-2 Sissy Nightstalker
S-3 Barb Barbee
S-4 LadyMango (Lynda)
S-5 BUMBLE GEE BEE (Gabi)
S-6 Sue Watz

Bill, AMA 4720
WACO Brotherhood #1









< Message edited by Stickbuilder -- 6/20/2008 4:11:21 AM >

_____________________________

It's easy, just glue all the pieces together, and sand off everything that doesn't look like an airplane.

(in reply to Stickbuilder)
       Post #: 6227

RE: WACO YMF - 5/7/2008 2:05:07 AM   
Hughes500E



Posts: 1047
Joined: 11/23/2002
From: Armstrong, BC, CANADA
Status: offline 		I agree, rudder is good I always use it as well but, I'd rather not fly around holding it over either )
No gas here, still running the 3 cylinder, just thought I'd share my find. 18-6 was spinning just over 7800

(in reply to Stickbuilder)
       Post #: 6228

RE: WACO YMF - 5/7/2008 3:02:46 AM   
Stickbuilder



Posts: 5219
Joined: 11/20/2005
From: leesburg, FL, USA
Status: offline
quote:

ORIGINAL: Hughes500E

I agree, rudder is good I always use it as well but, I'd rather not fly around holding it over either )
No gas here, still running the 3 cylinder, just thought I'd share my find. 18-6 was spinning just over 7800

The G-26 spinning a modified Zinger 18X6 has managed to turn almost 7900 rpm so far. It doesn't have much run time on it though. I doubt if I will ever approach those engine speeds on the plane.

Bill, AMA 4720
WACO Brotherhood #1

_____________________________

It's easy, just glue all the pieces together, and sand off everything that doesn't look like an airplane.

(in reply to Hughes500E)
       Post #: 6229

RE: WACO YMF - 5/7/2008 5:45:46 PM   
RICKSTUBBZ



Posts: 229
Joined: 10/26/2007
From: Hempstead, TX, USA
Status: offline 		I would like to share my point of view on engine thrust in Radio Control Airplanes. With many radio control airplanes you can get away with no thrust built into the engine mounting. However when you start dealing with an aircraft that has high lift or high drag factors all bets are off.

I agree that learning to fly with the rudder is of most importance in a quest to become a better pilot. Additionally, I would like to respectfully say, learning to properly trim an aircraft is just as important to be a better pilot and a better builder.

Where I fly we get many days with little to no wind in the summer time. And this is where you can easily see a thrust problem show up.

If you have no right thrust built in to an RC plane that needs it, you can trim the rudder to make the airplane fly a strait line from point “A” to point “B” but in doing so the tail is hanging out the left side (crabbing).

Then to get technical, one could go into the fact that now you have to trim left with ailerons to counter the roll coupling created by the right rudder that you are flying with. And if your airplane couples pitch (attitude /elevator) with the rudder, now you have to add elevator trim to compensate for that. All the while a little right thrust could have eliminated all of this.

It is just a matter of preference. With out a doubt even as little as 1° of thrust is a very noticeable difference on a 10” cowl. Personally I prefer to try hiding a skewed propeller so that I can have an airplane that flys strait.

< Message edited by RICKSTUBBZ -- 5/7/2008 7:11:07 PM >

_____________________________

Rick, AMA 115812
WACO Brotherhood #75

(in reply to Stickbuilder)
       Post #: 6230

RE: WACO YMF - 5/7/2008 7:48:01 PM   
WacoNut



Posts: 1484
Joined: 1/1/2005
From: Blanchester, OH, USA
Status: online 		It is all a matter of preference.
I started taking flying lessons in a full scale J-3 about 10 years ago and only logged 4 hours(long story) It made me a much better R/C pilot, I learned alot about trimming an aircraft and speed/energy management. The J-3 was a joy to fly and very easy, trim the plane up for level flight at 1800 RPM's and approx 65mph and if you wanted to climb add throttle when you wanted to decend reduce the throttle, the whole time the plane would maintain the 65mph that you trimmed it for. If you set your R/C plane up to fly at a nominal cruise speed at a given RPM it should climb with power and loose altitude with reduction in power. Once you get the hang of this and learn at what altitude to enter the pattern and at what throttle settings it will make you a much better pilot. To me it is all about speed management.
Anthony

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WACO Brotherhood #30

(in reply to RICKSTUBBZ)
       Post #: 6231

RE: WACO YMF - 5/8/2008 6:24:59 PM   
Thomas B


 

Posts: 439
Joined: 7/14/2002
From: Fort Worth, TX, USA
Status: offline 		And yet a goodly number of full scale aircraft do indeed have some right thrust built in, to minimize torque/P-factor/spiral propwash effects.

Yes, you do use trim and airmanship to get the final results you need, but aircraft often have some sort of compensation built in to help reduce pilot workload.

Look at a Cessna Caravan sometime..it has a remarkable amount of right thrust and down thrust built in. A considerable number of single engine aircraft have some right thrust built in. and, there are other compensation fixess as well.

Lots of full size aircraft do thrust line for pitch effects as well. A J-3 has no down thrust, but its big brother, the Pa-11 Super Cub has 4 degrees of downthrust built in.

Look at a side view of a Lake Amphibian sometime....massive upline thrust to counteract the high thrust line.

The modern line of RV experimental aircraft have right thrust built into the motor mount.

Older aircraft, such as the Aeronca Champ, often have the vertical fin offset to help with torque/-factor/spiral propwash. In fact, an article on the Waco club (full scale) website reccomends 1 to 4 degrees of fin offset to help with torque/P-factor/spriral prop wash effects:

http://www.americanwacoclub.com/newsletter/past/rigging_v1n3v1n4.htm

Lower powered full scale aircraft typically have the least compensation of these effects, while higher powered aircraft have a bit more.

Finally, some aircraft are rigged with one wing having a tiny incidence difference to the other wing to help with torque/P-factor/spiral prop wash.

Personally, I find it completely acceptable to do some thrust line adjustments on scale models to help minimize trim changes and needed pilot inputs.





< Message edited by Thomas B -- 5/8/2008 6:53:31 PM >

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Electric Coolhunter

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       Post #: 6232

RE: WACO YMF - 5/8/2008 8:22:59 PM   
Stickbuilder



Posts: 5219
Joined: 11/20/2005
From: leesburg, FL, USA
Status: offline
quote:

ORIGINAL: Thomas B

And yet a goodly number of full scale aircraft do indeed have some right thrust built in, to minimize torque/P-factor/spiral propwash effects.

Yes, you do use trim and airmanship to get the final results you need, but aircraft often have some sort of compensation built in to help reduce pilot workload.

Look at a Cessna Caravan sometime..it has a remarkable amount of right thrust and down thrust built in. A considerable number of single engine aircraft have some right thrust built in. and, there are other compensation fixess as well.

Lots of full size aircraft do thrust line for pitch effects as well. A J-3 has no down thrust, but its big brother, the Pa-11 Super Cub has 4 degrees of downthrust built in.

Look at a side view of a Lake Amphibian sometime....massive upline thrust to counteract the high thrust line.

The modern line of RV experimental aircraft have right thrust built into the motor mount.

Older aircraft, such as the Aeronca Champ, often have the vertical fin offset to help with torque/-factor/spiral propwash. In fact, an article on the Waco club (full scale) website reccomends 1 to 4 degrees of fin offset to help with torque/P-factor/spriral prop wash effects:

http://www.americanwacoclub.com/newsletter/past/rigging_v1n3v1n4.htm

Lower powered full scale aircraft typically have the least compensation of these effects, while higher powered aircraft have a bit more.

Finally, some aircraft are rigged with one wing having a tiny incidence difference to the other wing to help with torque/P-factor/spiral prop wash.

Personally, I find it completely acceptable to do some thrust line adjustments on scale models to help minimize trim changes and needed pilot inputs.





Not to be argumentative, but none of the airplanes that you mentioned were being built (or even conceived ) when the YMF was built in 1934. The Jacobs 225 can hardly be considered as a high performance engine.

Once again, what do you do when you have the offset engine thrust adjusted for cruise, and then change to a different throttle setting? Back to using the rudder and elevator. Right?

My YMF has an in-flight adjustable horizontal stabilizer (as did the full scale). The full scale had a ground adjustable trim tab for the rudder. You control your up lines and torque reaction during the take off roll with the rudder.

Engine thrust lines and propellor mis-alignment is noted during the static judging at Top Gun as well.

Bill AMA 4720
WACO Brotherhood #1

_____________________________

It's easy, just glue all the pieces together, and sand off everything that doesn't look like an airplane.

(in reply to Thomas B)
       Post #: 6233

RE: WACO YMF - 5/8/2008 9:00:05 PM   
khodges


 

Posts: 5060
Joined: 7/3/2003
From: newton, NC, USA
Status: offline 		When I "un-arfed" my UMF, I took all the right thrust out by using longer standoffs on one side of the mount. With the G-26 and an 18-6 MA Classic prop, there is a noticable torque reaction any time you "pour the coal" to it, either on take-off or while in the air. Application of right rudder is sufficient to control the tail on takeoff, and right rudder plus a little right aileron will compensate while in the air, unless your airspeed is close to stall, in which case it will try to snap roll to the left. Modulating the throttle by smooth "roll-on" rather than "jamming" it is the key at lower airspeeds, and a safe take-off means letting it build plenty of speed and fly itself off.

Mine also does tend to "crab" a little while in straight and level at cruise, however, I find myself using only a click or so of right rudder trim to straighten it out, with no aileron compensation. I believe it doesn't require aileron input because, the torque reaction to the left would also induce a roll couple to the left (it does, if left uncorrected) and the right rudder trim induces a roll couple to the opposite (right) side, cancelling the coupling tendency. I haven't noticed any elevator trim compensations needed, except the intitial trim for the desired airspeed. My plane is heavier than most of yours, I believe (unless you use a lead-based glue, like I apparently did) so my flying speed and approach speed is likely a bit faster than yours also. I cruise at about 2/3 throttle, descending approach is about 1/2 throttle, and short final is about 1/4 or a bit more, depending on whether it is still air or into the wind (forget downwind landing with this anvil.....er, plane) At any rate, I like how mine flies, at cruise speed the surfaces have plenty of authority, and I have twice the "up" as "down" in my aileron differential. The elevator is especially effective, and I use about 50% expo to try and "dull the edge" to make it less sensitive.

When at CCA last year, John and I noted that there were several UPF-7's with an offset V-stab, and asked about it. The answer I remember was that they were probably changed during restoration, or may have been an assembly line mod late in the series. John, have you learned any more about this?

< Message edited by khodges -- 5/8/2008 9:02:31 PM >

_____________________________

Club Saito #2, WACO Brotherhood #20. What other trouble can I get into?

(in reply to Stickbuilder)