Flap area Differential

[Larry Fernandez]

I completely understand why we build our planes with a longer in board wing, but why is it common to make the out board flap wider?

Larry, Buttafucco Stunt Team

[Dan McEntee]

   To allow for more tip weight to be carried for better line tension and still keep from banging a wing on loops and square stuff. At least that's what I remember from back in the day.
    Type at you later,
     Dan McEntee

[Jim Hoffman]

Dan is correct. I often tape on tabs to the OB wing or flap to permit experimentation with added tip weight. 

[Dennis Adamisin]

I completely understand why we build our planes with a longer in board wing, but why is it common to make the out board flap wider?

Larry, Buttafucco Stunt Team

Primarily, it counteracts the longer inboard wing...

[Brett Buck]

I completely understand why we build our planes with a longer in board wing, but why is it common to make the out board flap wider?

Larry, Buttafucco Stunt Team

  Probably because you don't also make the inboard stab longer. I don't either, I just put on or build in some tab. Also, "equal span" doesn't solve the problem, because the outboard wing sees a bigger speed differential than the (equal span) stabilizer.

       It's close enough to trim out, if you just accept you have to try it and see, and adjust accordinly.

     Brett

[Larry Fernandez]

Thanks guys! I have always built this way, because the hot shots have told me to do so. I just ever understood the logic behind it. When it comes to stunt, I  ever question Brett, Ted or David. I just do it. But I’ve always wondered why the wider out board flap works.
Thanks guys!!

Larry, Buttafucco Stunt Team

[Brett Buck]

   To allow for more tip weight to be carried for better line tension and still keep from banging a wing on loops and square stuff. At least that's what I remember from back in the day.
    Type at you later,
     Dan McEntee

  "Carrying more tip weight" is kind of right, but simply having more tip weight doesn't help you unless it also rolls the airplane, i.e. it hinges. The idea it to correct a situation where the airplane seems to need different amounts of tip weight at different load factors. For example, suppose you get it to fly flat through round loops with a given amount of tip weight, but then you find when you get that right, it wants to roll away from you in hard corners. This suggests you have the right amount of tip weight for rounds but need less for the squares .

     If you try to take some out to make the squares better, then it will be rolling in at you in the rounds and be much lighter in level flight. This situation suggests you need some additional outboard tab.   So, in that case, you end up "carrying more tip weight" by putting on a tab, but you are just trying to make it so whatever tipweight you have is right for all conditions, not necessarily that there is more of it.

      What *most* people wind up with is more tab than would be perfect in all conditions. If you have excess tab, you set the tip weight to be flat in hard corners but with some non-zero outboard roll in level flight and the rounds. That's because you can tolerate small amounts of roll in the rounds much more easily than squares.

   But simply doing something to "carry more tip weight" is sort of a misleading idea, you never want any more than is necessary to fly through hard corners without hinging
 
     Brett

[doug coursey]

ON EQUAL LENGTH WINGS WOULD YOU RECOMEND MAKING THE INBOARD FLAP SMALLER THAN THE OUTBOARD..

[Dan Berry]

ON EQUAL LENGTH WINGS WOULD YOU RECOMEND MAKING THE INBOARD FLAP SMALLER THAN THE OUTBOARD..

I know two reasonably capable fliers who advocate that.

[Dave_Trible]

ON EQUAL LENGTH WINGS WOULD YOU RECOMEND MAKING THE INBOARD FLAP SMALLER THAN THE OUTBOARD..

Well, I do.   I use equal span wings and make the outboard flap chord about 3/32" wider full span.  That equates to about the same thing as a flap tab or 'wart'.  Every airplane is a little different but this gets me in the ballpark 98% of the time.

Dave

[doug coursey]

Well, I do.   I use equal span wings and make the outboard flap chord about 3/32" wider full span.  That equates to about the same thing as a flap tab or 'wart'.  Every airplane is a little different but this gets me in the ballpark 98% of the time.

Dave

IM BUILDING A NOBLER WITH EQUAL SPAN WING AND GETTING READY TO SILKSPAN THE FLAPS..I COULD NARROW THEM UP VERY EASILY NOW

[Dave_Trible]

Well I think I would build the Nobler as it was designed.....However in terms of flap asymmetry,  I think in terms of ADDING area, NOT removing it.  Make the outboard flap bigger-not the inboard smaller.  Don't give away lift.  Make a new flap or add a strip of wood to the original.

Dave

[doug coursey]

I MADE THE OUTER WING THE SAME SIZE AS THE INNER WING SO THE WING AND FLAP IS LARGER THAN ORIGINAL.....

[Dave_Trible]

Well good but by how much?   If about an inch (which I suspect ) then I'd just call it good.  Honestly I doubt you'll be able to tell much difference.  This may enable you to carry maybe another 1/4 ounce of tip weight than you would otherwise which MAY yield a little more line tension.  You'll have to finely adjust that once you start flying.  I usually start a bit light on tip weight and put on chunks of clay until I go a little past ideal.  I then weigh the clay in grams,  pull a little out then add lead in the weight box or cutting a small slit in the covering and patch the hole.  Once the amount is set you shouldn't have to adjust it again as long as you don't make any big changes to lines weight or length and fly the airplane at about the same lap time.  I will on occasion stick on a little more weight when having to fly in stronger wind than normal.  Tip weight and flap asymmetry are really two separate trim issues which at the highest levels should be analyzed and dealt with separately but they still work hand in hand so can be dealt with together for basic trim. 

Dave

[Brett Buck]

Well I think I would build the Nobler as it was designed.....However in terms of flap asymmetry,  I think in terms of ADDING area, NOT removing it.  Make the outboard flap bigger-not the inboard smaller.  Don't give away lift.  Make a new flap or add a strip of wood to the original.

Dave

    While I agree with the idea of leaving it as is (and then probably adding tabs during trimming), and with all due respect, this is not a good reason. Cutting down the flap does not "give away any lift", because it is impossible to deflect the stock flap very far (hinge moment) or generate much AoA (pitching moment) with the rest of the airplane unmodified.

      Even if you ignore that, and assume you can get a big one and a small one deflected the same angle, making it a larger fraction of the chord is a very weak function, you go from 20% of the chord to 40%, it's under 10ish% increase in the Cl. So for a given hinge moment, you get a much bigger Cl increment by deflecting a small flap through more angle than you do deflecting a large flap through a smaller angle.

    Noblers and the innumerable clones greatly benefit from either cutting a large amount off both flaps, reducing the flap throw WRT the elevator, or both. Bob Gialdini pointed out the same idea in the Olympic article, Ted's experiment with the Imitation demonstrated it in droves. Even Big Jim understood it, he was experimenting with giant flaps but also knew that he had to greatly increase the stabilizer authority by making it also huge, and also trim for absolutely astronomical line tension to be able to force the flap to deflect far enough to do more harm than good. There's more going on in Big Jim/Windy's case, but they at least recognized the problem.

     Even the near Nobler-clone Tucker Special experiment dealt with the same problem, in that case accepting the requirement to somehow increase the line tension/control deflection without flying it faster (which adds tension but also adds hinge moment at the same time and to the same degree), because it was not in the spirit of the rules to cut down the flaps, and too difficult to cut into the airplane and adjust the flap/elevator ratio.

    Take a box-stock Green Box Nobler with the stock controls arrangement and the typical 42-45 ounce weight,  and you could very greatly improve the cornering by cutting about an inch off the flap chord at the root down to about 1/4" off the chord at the tip. This is more or less what Gialdini recommended, and more or less what fixed other "giant flap" models like the Profile Cardinal.   I don't recommend that, because a Nobler is really only competitive in Classic, and classic means you have to leave the design more-or-less as it comes and just deal with it.   But it's absolutely no problem shaving a bit off to get a built-in tabm because the flaps are vastly too big in the first place.

      Brett

[Dave_Trible]

I'm sure you are right...IF your airplanes are on the light side.  I have a bad habit of building airplanes that are on the heavier side of the desired range.  Some of that is trying to make the airplane sturdy enough to last a while flying off sort of rough turf most of the time.  The Nats is usually the only pavement flying I see.  I have had a couple that would stall on occasion and I'd have to fly them more carefully until I added flap area/chord to create enough lift to carry the airplane through hard turns and overheads without stalls.   Power was never a problem but lift can be.  I don't use adjustable control linkages -and use close to 1 to1 ratios anyway- so adding area is how I make them work for me...My newest airplanes are quite a bit lighter.  I'm eager to see if they hold up a couple seasons.  It may also be that some of the older designs had an abundance of flap area.   They also sometimes had pretty heavy wood in the kits.  Could be the flaps helped insure reasonable performance on average.

Dave

[doug coursey]

i changed the flap to ele ratio also 1 inch on the flap and 3/4 inch on the ele horns so i have more ele throw than flap,the elevators are a bit small so increased the throw...

[Brett Buck]

i changed the flap to ele ratio also 1 inch on the flap and 3/4 inch on the ele horns so i have more ele throw than flap,the elevators are a bit small so increased the throw...

   That's a good idea, and I would suggest that you make it adjustable if possible, because if the airplane is very light or has a more-powerful-than-a-Fox engine, it might need even less than that.

       Brett

[Dennis Adamisin]

I MADE THE OUTER WING THE SAME SIZE AS THE INNER WING SO THE WING AND FLAP IS LARGER THAN ORIGINAL.....

Hi Doug
I like equal span & equal size flaps.

I have built many airplanes from equal span to 3.5" offset (All American Sr), most all of them can be trimmed to fly pretty well regardless of the offset (even the AA Sr), but in the end the offset wings all want to hinge.  Hinging is not a death sentence but it is one of those quirks that you just learn to live with.

Been flying an airplane (not my own design) with longer inboard wing with a larger outboard flap for the past couple years; it flies great, and it hinges.  Even when I remove too much tip weight, it hinges.  Even after I added a 1/2" x 4" tab to the already larger outboard flap. it still hinged. Its slight, not enough to show up on the scoresheet but its still there.

I have no bones to pick with other designers, but when I design my own my poison of choice is equal span & equal flaps...

[doug coursey]

with 1'' at the flap horn and 3/4' at the elevator i have at 10 deg ele i have 3 deg flap,at 20 deg ele i have 13 deg flap,at 30 deg ele i have 24 deg flap,at 40 deg ele i have 30 deg flap....

[Brett Buck]

I have no bones to pick with other designers, but when I design my own my poison of choice is equal span & equal flaps...

   The real answer is that asymmetry anywhere in the ballpark is OK. The right answer for a 40-60 sized stunt plane is somewhere around 1", but you can trim out about equally well anywhere from 1 1/2 down to 0 on a regular-sized (60" span) airplane with proper use of tabs. Some people have even been known to use backwards asymmetry, that can be dealt with in small amounts.

    The big difference between the correct ~1" and 0 is that it takes way more tip weight for 0, maybe twice as much or more, with everything else being equal. That is not an advantage of "carrying more tip weight" because that is not an advantage in the sense it is usually meant. You wind up trimmed at about the same roll angle, so the line tension is the same. You just have to use more weight to do it.

  I think the "carrying more tipweight" thing stems from something Al Rabe said that was roundly misunderstood. Al said something like "Adding tipweight always adds tension", which is true in a static situation and as long as you don't change anything else. It is not generally true in a dynamic sense, because while it will add tension as you start a corner, it will get much lighter very shortly thereafter as the airplane swings back from a positive to negative roll as the lines and the line tension try to restore the roll angle.

     The very first thing thing to happen is that you get a big increase in the tension as the airplane rolls away from you because you have a component of the lift in the outward radial direction which adds to the tension. Then it will come shooting back the other way, rolling inboard and subtracting the lift from the line tension, then oscillate. While the line tension is changing all over the place, the control deflection is also changing, tightening up the corner when you have more and opening it up when you have less. This is why hinging is so bad and you can't expect to fly competitively with any significant hinging.

  So, that is taking a specific airplane is a specific state of trim, and then doing nothing but adding tip weight to it, and to some degree of approximation Al was right. Adding tipweight and adjusting or bulding in aerodynamic features to keep it from rolling/hinging give you essentially a net zero, no additional line tension at all, aside from the fact the airplane weighs an ounce more. So being able to "Carry more tip weight" is really no advantage.

    Brett

[Howard Rush]

I just measured Gordan’s famous profile twin. It’s completely symmetrical, except for the engines. The left engine is a tad closer to the centerline than the right.

[Ken Culbertson]

I just measured Gordan’s famous profile twin. It’s completely symmetrical, except for the engines. The left engine is a tad closer to the centerline than the right.

This is a very interesting discussion.  I am building a twin and horizontal weight distribution is an issue.  The more I ponder on equal span the better it sounds.  It definitely solves one of the problems I have faced - not checking which wing I am putting the leadouts in while it is on the jig upside down.     If the plane was not tethered, having unequal surfaces would cause roll....just like it does when it is tethered.  So why are we creating roll only to correct for it with extra surface on the outboard flap?  If fuselage position determines which wing is larger then why does an All American Sr. fly level once it is up to speed with no flaps?  Why do most combat wings fly flat with no fuselage at all.

Now one argument I can buy is that offsetting the fuselage is simply moving the horizontal CG over the center of lift since the inboard wing is flying slower than the outboard.  So, the fuselage is really just tip weight?  But the outboard is also creating more drag, OMG yaw.  Ah, but the lines are countering that.  Maybe I should just build the damn thing and trim it however it comes out.  Seems like there is no "right" answer to this question.

Sorry, I haven't had my coffee yet - Ken

[Brett Buck]

This is a very interesting discussion.  I am building a twin and horizontal weight distribution is an issue.  The more I ponder on equal span the better it sounds.  It definitely solves one of the problems I have faced - not checking which wing I am putting the leadouts in while it is on the jig upside down.     If the plane was not tethered, having unequal surfaces would cause roll....just like it does when it is tethered. 

    The last bit is quite wrong. You are continually yawing to the left, and the span of the airplane is an appreciable fraction of the turn radius. So the outboard wing is going faster than the inboard. The purpose of the asymmetry is to try to even out the dynamic pressure/lift difference caused by the velocity gradient. There definitely is some "correct" amount of asymmetry that evens out the lift differences and puts the lateral Cl at the middle of the fuselage. The right answer for a 35-sized airplane is about 1/2", the right value for a 40-60 sized airplane is about an inch.

     There was some idea about "moving the fuselage over" to act as tipweight, and the really big offsets were trying to save weight or avoid having to add tip weight. The All-American is a perfect example, it's about 3" - and the right value was about 1/2". Note that by moving the fuselage over, you are also moving the stabilizer and engine thrust line. That's why the All-American flys like it does - wild hinging and scary "yaw in at you'" takeoffs.  You can do something about the takeoffs by putting in large amounts of engine offset to line the thrust vector up with the CG, but to correct the hinging you would have to also scoot the stabilizer/elevator to the left as well - or, do like Kaz did and cut 2.5-3" off the inboard wing.

      The problem is that the lift distribution is not necessarily the same at different load factors, that is why you need some sort of tab. Effectively, you need different amounts of asymmetry at different load factors, which you are compensating for with some sort of differential flap area that alters the lift distribution at different control deflections. I have seen a few I-beamers with large amounts of asymmetry  - to try to save weight (in piddling amounts in the big scheme of things) - that wound up with a normal-looking inboard flap and an outboard flap so large that it was almos constant-chord. In the opposite direction, some "equal span" wing airplanes end up with tabs on the inboard wing.

      I would also note that in the good old days, and even now for people who don't seal their flap hinge lines and/or don't shape them correctly,  there are potentially much larger *random" effects that obscure the minor effects of asymmetry. Random hinge line leakage, even with the tiniest of difference between the inboard and outboard, can completely swamp the effects of asymmetry. Same with "flap fillers"/partial span flaps, particularly if you are trying to use one of them as a roll tab, that is another random factor that can completely overwhelm or obscure the effects of asymmetry.

    So, equal-span, or >>1" are both definitely not right and the reasoning you use above ignores the velocity gradient. I also note that the same reasoning applies to the tail, and I have added extensions on the inboard stabilizer and elevator that suggested I could remove some of the built-in tab effects on several of my airplanes .

   But again, as mentioned every time this comes up and everybody wants to argue about it again   ---   it is not that critical, and you can trim it about equally well with any asymmetry between about 0 and an 1 1/2" on conventionally-sized airplanes, probably because even the smallest random factors require you to determine it by cut-and-try.

      Brett

[doug coursey]

IM GOING TO BUILD A TUCKER SPECIAL WHEN I FINISH THE PLANE IM WORKING ON NOW...I HAVE SOME SHEETED FOAM WINGS FROM BOB HUNT WITH A 1" DIFFERENTAL SO THE INBOARD FLAP WILL BE 1" LONGER THAN THE OUTBOARD..WHATS YOUR TAKE ON THAT AND THE SIZE SINCE ITS BASICLY A NOBLER WING..IM GOING TO PUT A JETT 40 N IT.

[Dan McEntee]

I just measured Gordan’s famous profile twin. It’s completely symmetrical, except for the engines. The left engine is a tad closer to the centerline than the right.

   I would have to get the article out to check for sure, but isn't the left (inboard) engine offset a bit more than the right? Could that be what you are seeing or measuring? It's been a long time since I read the article. I think this was to address a right engine out first scenario.
   Type at you later,
   Dan McEntee

[Steve Dwyer]

I'm building Gordan's Pathfinder twin right now. The plans show the outboard engine is offset 3 degrees while the inboard engine has no offset.  The outboard nacelle is closer to the fuse by approximately one quarter of the rib spacing than the inboard nacelle. I happen to be using a Brodak single Pathfinder kit to build from.

Steve

[Howard Rush]

I'm building Gordan's Pathfinder twin right now. The plans show the outboard engine is offset 3 degrees while the inboard engine has no offset.  The outboard nacelle is closer to the fuse by approximately one quarter of the rib spacing than the inboard nacelle. I happen to be using a Brodak single Pathfinder kit to build from.

Plans don’t match the original, then. Neither engine has offset. When one engine quits the only way to tell which quit is to look at wheel alignment.

[Howard Rush]

   I would have to get the article out to check for sure, but isn't the left (inboard) engine offset a bit more than the right? Could that be what you are seeing or measuring?

No and no, respectfully. Looks like the profile nacelles are equidistant from the fuselage, and the engines are mounted on the right sides of them, hence the thrust line asymmetry.

[Steve Dwyer]

Howard,

The article I have from Flying Models August 10, 2010 begins by saying "there have been many versions of Gordan Delaney's Pathfinder designs over the past several years, these are one of them". These plans called Pathfinder 2 are dated August 27, 2008 designed by Gordan Delaney and autocad by John Miller. Wasn't there also a twin plan by Eric Rule or did he just kit a Delaney version?

These plans do not have the nacelles equidistant from the fuse, have equal length wings on each side and the outer engine is offset 3 degrees. The engines are on the outside of each nacelle. Are the plans you are referring to earlier than these?

Now I'd like to know what the best design was.

Steve

[Howard Rush]

I haven’t seen plans other than a picture of plans showing the wrong airfoil. I have the actual airplane. It is a really good stunt plane.

[Steve Dwyer]

Lots and lots of twin stuff here in SH going back to 2008. I did verify that the RSM kit did use the Gordan Delaney design drawing dated 2006 (not 2008) as I said earlier, sorry I couldn't read the fine print in the magazine article and was too lazy to walk downstairs to view the prints. There are a number of positive testimonials including from Bob Hunt after flying the Delaney design. Gordon did post he was most satisfied with two .15 FP engines while others have felt using the .25 size works best if the model comes in heavy. Gordan's model with the 15s weighed 46 ounces. As for the design discrepancies in nacelle position and engine offsets, it appears the 2006 design as presented in the FM Aug. 2010 article was the final version. Onward....

Oh, BTW there was one discussion of where someone's electric version had the propellers rotating toward each other. This can be another discussion!

Steve

[Howard Rush]

Bob Hunt and other name-brand fliers flew the airplane that’s sitting in my shop. They are no doubt miffed that they were tricked into flying an imposter.

[Steve Dwyer]

So, Howard based on the flying results from the 2006 plans build and your "mystery ship" with no plans (??) it appears we can conclude the dimensional variations and offsets have little effect on flight. We do know nacelle alignments are critical and requires extra care and jigging.

[Paul Walker]

I haven’t seen plans other than a picture of plans showing the wrong airfoil. I have the actual airplane. It is a really good stunt plane.

Howard,

Who built your "actual" airplane?

[Brent Williams]

Howard is the owner of Gordan's former plane. 
Gordan uses a molded leading edge on his planes.  The leading edge has a more blunt, ellipse style leading edge profile than the Brodak kit version. 
The trailing edge is slightly thicker to accommodate 5/16" thick(I think) tapered flaps as well. 

[Howard Rush]

Howard,

Who built your "actual" airplane?

The twin?  Gordan Delaney, I presume. There it is with him in the picture.

[John Miller]

I just measured Gordan’s famous profile twin. It’s completely symmetrical, except for the engines. The left engine is a tad closer to the centerline than the right.

After all the questions related to my friend Howard's post, quoted here, I took a look at the actual drawing files from the published drawings. The design is symetrical, including the engine thrustline distances, 6" from centerline, each side of the fuselage.

Howard has a noted very dry wit. I believe he might have got you, me.

[Steve Dwyer]

After all the questions related to my friend Howard's post, quoted here, I took a look at the actual drawing files from the published drawings. The design is symetrical, including the engine thrustline distances, 6" from centerline, each side of the fuselage.

John,

There seems to be some confusion here. The Drawings dated August 27, 2006 in the Flying Models August 2010 article you authored shows a symmetrical wing but the engine thrust lines are not equal distant from the centerline of the fuse. They vary by 1/2" And for verification the outboard engine only is offset 3 degrees.

Please confirm the correct configuration, Howards model or the 8/27/2006 design drawing?

Steve

[Steve Dwyer]

Here's the 2006 drawing title block.

[Steve Dwyer]

Somewhere here I read someone said Howards model was a comfort to fly with little pull. With no engine offsets and equidistant nacelles this would be expected. The 2006 drawing shows the moment caused by the farther inboard nacelle and offset on one engine would certainly add pull. The question is why was the change made?

Steve

[John Miller]

Hello Steve. I have an answer for you, and others , several actually.

Gordan's twin was built after the plans were drawn, as was mine, (the yellow & blue one in the above picture), and like many scratch builders, he made slight changes to reflect his personal preferences. He likes to double the sheeting out one or so rib spaces past the fuselage to strengthen the wing at the fuselage joint. He generally doesn't like any changes in the engine thrust line, so, he opted out of any down, or outboard out thrust.

While there is a very tiny difference in the symmetry between the  nacelles on the original Dwg file, Most builders never build to the accuracy to make it relevant.  This error, which I agree should have been noticed before, places the outboard nacell thrustline about .003" closer to the fuselage side than the inboard side. (5.75" verses 5.72")  I changed from using 6" from the engine mounting surfaces, to the centerline of the 1/2" thick fuselage as I soon found out that was going to be difficult to measure when locating and aligning the nacelles, so it was changed to referencing  to the sides of the fuse. Spacing the nacells using the fuselage engine mounting surfaces also relates to the thrust lines at 0-0, and it's the prop centers we want symetical.

As you are probably aware, some strange things often happen between the original .Dwg Cadfile, and the drawing you windup with.  It's often been printed or rendered into a pdf by someone else, occasionally not understanding what they are doing. Creep and sizing to their window are just 2 that I'm aware of.

Still, a lot of PF Twins have been built during the 15+ years since the design was published. I'm sure many had changes built in, either on purpose or by accident. Over and over, they tend to fly well. There is the built in apparent advantages to twins, like a large combined Prop Disc Area that covers a signficant area of the wing. Some like to use a .25, on the PF-2 which I personally believe is overkill, but they fly well also.

It's my opinion, based on my experience from the twins I've built and flown, that more important than absolute perfect symmetry, within reason of course, ('cause how many of us hold a toleranmce of .003"?), is how straight, how strong where needed, our planes are built. How smooth, accurate, and equal our sealed controls are, and most importantly, how well everything is ALIGNED. Gordan built a special jig, and spent hours, to set up & align all the moments during final assembly of his Twin. The O.B. thrust's there to help in an outboard engine out situation, but you don't have to use it if you're confident with your skills. but, ' two'nt hurt tho...

I can tell from the title block you attached that it has gone through at least 2 sets of hands or printings, since the original.

I've posted sheet 2, the title block is from the original drawing. It also shows te entir wing const.

Thanks for your help in identifying, clarifying this, and members, please excuse me for the topic-creep.

John Miller

Howard still has a well developed,very dry sense of humor! Thanks Howard for being there.

[Steve Dwyer]

John,

Thanks for your response and your supportive PM as well.

In the interest of the readers that may be curious, my decision after having John's and Bob Hunt's recommendations is to have the nacelles equidistant from the center line of the fuse. Make the inboard wing slightly longer and tweak the flap chord dimensions. Because I have already built both nacelles with 2 degrees in the outboard only instead of 1 degree in both as Bob suggested I've decided to leave it. I have built the fuse with the built out skinned configuration instead of the solid plank as per the Delaney plan, this has dropped its weight by .5 oz and has reduced the twist considerably.


Steve

[Steve Dwyer]

The Pathfinder Twin on the bench ready for assembly and finishing.

Steve