Author Topic: Engine in-line with wing (Read 4254 times)

Bob Reeves · « **on:** May 12, 2008, 10:13:29 AM »

Know a couple designs used an in-line aproch.. Just wondering what quirks might be linked to an engine in-line with the wing and if anyone has ever managed to get one to fly well...

Just One-eye · « **Reply #1 on:** May 12, 2008, 12:14:12 PM »

The problem is similar to what happens when you mount the wing very low in the fuselage without adding a dollop of dihedral. With one, you get a vertical CG below the middle of the structure because of the gear, while with the other, you get the CG too far above the wing, so the plane wants to hinge on the leadouts, outside wing out of line high and low.

Tom Dixon has experimented with Zero-zero setups, and so did Bob Baron.

Bob Reeves · « **Reply #2 on:** May 12, 2008, 03:04:30 PM »

Lets assume the engine is side mounted with the stab slightly above the wing and the vertical CG is OK

RandySmith · « **Reply #3 on:** May 12, 2008, 09:47:33 PM »

Quote from: Bob Reeves on May 12, 2008, 10:13:29 AM

Know a couple designs used an in-line aproch.. Just wondering what quirks might be linked to an engine in-line with the wing and if anyone has ever managed to get one to fly well...

Bob
I have watched very many over the years,and have flown many of them too, The best one I have seen fly without having to fly extra fast and didn't have the quirks , was one with the engine side mounted. If you want to build one that works well try Bill Werwages Sidewinder Geo XL

Randy

Geoff Goodworth · « **Reply #4 on:** May 14, 2008, 06:00:38 AM »

Bob

Tony Eiflander modified his Freebird design some years back to run his big PAW diesel sideways and placed reasonably well, if I remember correctly, in the Olde Dart.

I have some info on the mods to the published Freebird 3 plan that I can dig out for you if you want. Otherwise, you might find something on Tony Elmore's site.

Cheers

Geoff

Bob Reeves · « **Reply #5 on:** May 14, 2008, 10:54:11 AM »

Thanks Gang,

A search brought up this very interesting thread http://stunthanger.com/smf/index.php?topic=327.0

It starts out talking about stabs but gets into full boat in-line configurations later.. Looks like if I do have a hunting issue a little more engine down thrust just might cure it but think I need to read that thread about a dozzen times before it will all sink in.....

fred krueger · « **Reply #6 on:** May 15, 2008, 02:40:36 PM »

BTW, the Yatsenko 'Shark' is an in-line design. This plane won Open and Advanced at the 2007 NATS.

Fred

Alan Hahn · « **Reply #7 on:** May 16, 2008, 07:32:35 PM »

Quote from: Fred Krueger on May 15, 2008, 02:40:36 PM

BTW, the Yatsenko 'Shark' is an in-line design. This plane won Open and Advanced at the 2007 NATS.

Fred

Fred,
Good point. How fast we forget!

phil c · « **Reply #8 on:** May 18, 2008, 10:29:25 AM »

All designs have quirks. The main one regarding thrust line/wing/stab and fuselage side area distribution is to get everything balanced so the plane is completely neutral. The RC pattern folks and full scale aerobats have worked on this a lot. Try doing knife edge(reverse wingover) with a low wing plane with minimal dihedral, a high stab, and a big fin and rudder. With all the controls in neutral it will naturally turn quite hard towards the canopy(if I'm keeping up and down straight). The CAP20 is a good example. It has a lot coupling between the controls. The RC guys use computer radios to mix in the proper amount of control, we have to add elevator, which makes the maneuver harder. An inline plane tends to turn slightly towards the gear.

For CLPA, anytime the plane gets above 30 deg. or so this coupling will start to come into play. It also interacts with the wind.

Ward Van Duzer · « **Reply #9 on:** May 26, 2008, 01:12:30 PM »

Mikey Pratt's original full-flapped profile Force was a total inline design. Engine, wing, and stab. Yup, side mounted engine, Mag .36 and slipped a pipe under the wing. Built in '92 or thereabouts, and I still love it. No hunting problem at all.

W.

The bottom 2 are mine, the 2 in the right side of the colage are Mikes. his profile, and his Magnum force.....still a cool looker!

peabody · « **Reply #10 on:** June 07, 2008, 08:56:10 PM »

Bill Werwage was sneaking up on in-line designs....

Bill Little · « **Reply #11 on:** June 22, 2008, 12:24:55 PM »

Quote from: peabody on June 07, 2008, 08:56:10 PM

Bill Werwage was sneaking up on in-line designs....

HI Rich,

He was more than sneaking up on them, he had them full blown. See Randy's post above concerning the first Geo XL which was a sidewinder. If he could have worked out the header problems, it would have erally been awesome. As it was, the design flew great, but the convoluted header gave fits. The Geo *Bolt* XL (Geo XL with T-Bolt wing) that Aaron built and flew was an inverted engine, but the stab and wing were basically 0-0.

Mongo

RandySmith · « **Reply #12 on:** June 26, 2008, 10:06:19 AM »

Quote from: Bill Little on June 22, 2008, 12:24:55 PM

HI Rich,

He was more than sneaking up on them, he had them full blown. See Randy's post above concerning the first Geo XL which was a sidewinder. If he could have worked out the header problems, it would have erally been awesome. As it was, the design flew great, but the convoluted header gave fits. The Geo *Bolt* XL (Geo XL with T-Bolt wing) that Aaron built and flew was an inverted engine, but the stab and wing were basically 0-0.

Mongo

Hi Mongo

Actually he didn't fly much after,That was fixed, I made a "real "header for that ship , although very late in it's life, but that fixed the header breaking problem Billy had with the inline ship

Randy

peabody · « **Reply #13 on:** June 29, 2008, 07:56:24 PM »

It seems to me that the biggest problem with in-line is that the landing gear needs to be inordinately long!

Bob Reeves · « **Reply #14 on:** July 09, 2008, 10:52:44 AM »

Quote from: peabody on June 29, 2008, 07:56:24 PM

It seems to me that the biggest problem with in-line is that the landing gear needs to be inordinately long!

Not if it's fuselage mounted and the fuselage is ahaped like a Shoestring

Alan Hahn · « **Reply #15 on:** July 18, 2008, 01:09:32 PM »

Quote from: Fred Krueger on May 15, 2008, 02:40:36 PM

BTW, the Yatsenko 'Shark' is an in-line design. This plane won Open and Advanced at the 2007 NATS.

Fred

Looks like you can add 2008 NATS to this too (assuming O.H. was flying the same plane).

added: after looking at Dennis V's photos-----oops, looks like Orestes Hernandez's plane is not the same as last year!

added 7/21/08 Fred tells me that Orestes Hernandez Shark was named "Legacy", so it did win again! In-line rules for 2 years in a row!!!

steven yampolsky · « **Reply #16 on:** August 06, 2008, 05:12:02 PM »

Quote from: Bob Reeves on May 12, 2008, 10:13:29 AM

Know a couple designs used an in-line aproch.. Just wondering what quirks might be linked to an engine in-line with the wing and if anyone has ever managed to get one to fly well...

Most East European designs are inline sidewinders. Humpback canopies and tall rudders are needed though to offset the drag created by the tall gear.

Howard Rush · « **Reply #17 on:** October 14, 2008, 01:09:35 PM »

I flew a Shark quite a bit last weekend. The relationship between inside and outside maneuvers was no different than with the Impact, and I don't remember any difficulty in flying level, either right side up or upside down. I couldn't tell any other difference that I'd attribute to the thrust line or engine orientation. It did take off and land a little differently, but I think that was because the Shark I flew had more wheel friction than my plane does.

MikeyPratt · « **Reply #18 on:** October 20, 2008, 09:56:39 AM »

Quote from: Howard Rush on October 14, 2008, 01:09:35 PM

I flew a Shark quite a bit last weekend. The relationship between inside and outside maneuvers was no different than with the Impact, and I don't remember any difficulty in flying level, either right side up or upside down. I couldn't tell any other difference that I'd attribute to the thrust line or engine orientation. It did take off and land a little differently, but I think that was because the Shark I flew had more wheel friction than my plane does.

Hi Howard,
This seems to come up from time to time and although I like the “in-line” designs I’ve had great success with flying either one. At one of the team trials, I watched Billy fly the “In-Line Geo XL” and though WOW, does it ever present itself well (I think it had more to do with the overall shape of the model). I was flying the Magnum Force and we sat and talked about the Pro’s & Con’s of “In-Line designs” and we were both of the same opinion that either could be trimmed and flown very well without much trouble.

Ward,
The Primary Force and the Force are true “in-Line” designs and their flying abilities have proven to be very good. The Magnum Force had the wing & stab in-line with the engine offset .625 above the wing and stab. This allowed the pipe to fit under the wing without making the fuselage appear overly portly. The HP Gold Cup was radial mounted and canted at the 7:00 position to hide the side to rear header and to align the engine header to the pipe inside the fuselage. All & all, the Magnum Force had a very pleasing organic shape to the fuselage of the model. It also flew extremely well and easy to trim. On its 25th flight I signaled for an official at the Nat’s and placed her in the top 20.

Later,
Mikey

Willis Swindell · « **Reply #19 on:** October 20, 2008, 12:23:57 PM »

I have flown my Phoebus for about 4 years now and haven't noticed any difficulties. just use light wheels or tilt the engine up about 20 degrees.
Willis

Dean Pappas · « **Reply #20 on:** October 21, 2008, 10:06:29 AM »

Hello Willis,
Is that an RCV 4-stroke in the red ship?
Any setup info?
Dean Pappas

Willis Swindell · « **Reply #21 on:** October 21, 2008, 06:44:01 PM »

Dean
I made a venturi for my RCV .288 with a Super Tigre needle and seat. This engine is the most docile of all the 4S. Does not like castor oil. DO NOT use more then 5% castor . The biggest problem is the power to weight ratio. It has the power of a Saito 50 but weighs much more I forget the weight but it is heavy. It would not pull my Phoebus as well as my Saito 56 and the plane was a lot heaver and did not fly as well as my other Phoebus. I Pulled it out and put in a Pathfinder, that I took a Saito 50 out of. Now the Pathfinder is heavy enough that it doesn’t turn very well.
Willis

Willis Swindell · « **Reply #22 on:** October 22, 2008, 08:48:53 AM »

Does any one have trouble getting equal flap and elevator movement on inline planes ? On one of my Phoebus I used a second pivot arm to change direction of the push rod and to align it with the elevator horn.
Willis

MikeyPratt · « **Reply #23 on:** October 23, 2008, 11:33:42 AM »

Quote from: Willis Swindell on October 22, 2008, 08:48:53 AM

Does any one have trouble getting equal flap and elevator movement on inline planes ? On one of my Phoebus I used a second pivot arm to change direction of the push rod and to align it with the elevator horn.
Willis

Willis,
The short answer is yes. The angle of the pushrod is greater on in-line designs than a conventional layout. To get the control throws equal I did the geometry in CAD to set the horns at the correct angle before building the model. If I remember correctly, this turned out to be about 1.25° reward for the flap horn and 1.25° forward on the elevator horn. This worked great on the Magnum Force. The Force (profile) was easy to do by installing the plastic flap horn back from the center of the hinge line and the elevator horn forward to the hinge line.

Later,
Mikey

Willis Swindell · « **Reply #24 on:** October 23, 2008, 11:58:05 AM »

Mikey
Thanks for the information. I’m thinking about building another Phoebus with a built up wing and try to reduce a little weight. I will copy the information and keep it handy.
Willis

Serge_Krauss · « **Reply #25 on:** October 24, 2008, 11:09:40 PM »

> Does any one have trouble getting equal flap and elevator movement on inline planes ?

Check my "Trig Problem" thread, most of the way down the page on SSW Forum. I'm making a device to measure the relative deflections of flap and elevator with various ratios of horn length to rod length. With a preliminary measured sketch though, I found that things worked pretty well within 40+ degrees of deflection with equal flap and elevator horns, when they were configured so that the line from hinge to rod attach point is kept perpendicular to the rod. Mikey gives an easy way to achieve or approximate this above. You can also use Larry Cunningham's "Magic Geometry" and just tilt it so that the hinge axes are located in line; that should ensure good agreement between flap and elevator deflection. I suspect that deviating fromthis scheme can cause problems. The greatest deviation is probably from bellcrank to flap horn, and I'm going to look at that too. One respondent using a 7" rod there found good results though. My current project is an in-line design. I don't expect problems.

SK

Author Topic: Engine in-line with wing (Read 4254 times)

Alan Hahn

Alan Hahn

steven yampolsky

Willis Swindell

Willis Swindell

Willis Swindell

Willis Swindell