Aerobat extended wings

[klares 1]

Been reading a bunch lately can't seem to find info on anyone extending the aerobat wings to hh length. A plane I'm looking at has them. Can anyone explain how this would have been done what effect it may have on the plane?

Seen the post on the extended speed wings but I'm guessing there must be some differences.

[EDMO 1078]

klares,

     I understand that Avid made a kit to extend the wings.   Some used the kit to extend their 29' regular Avid wings to the length of the 32' Kitfox wings.

 I think the Aerobat was made with stronger, or equal to the HH wings, only shorter. 

     Guessing they were the Speedwing ribs? 

 I have the Aerobat acrobatics manual, but with the longer wings it might not be applicable.

     I am a Kitfox type builder, and only have the Avid Magnum manual and the Aerobat flight maneuvers booklet.

I would bet that Doug Holly has the info you are looking for.

EDMO 

Edited 30 Jun 2015 by Ed In Missouri

[dholly 718]

Personally, I'm not a fan of wings extended with the 'add-on kit'. Almost every post I've read has said the kit resulted in no top end gain and little, if any, STOL performance gain. To grasp why that is, you need to understand the (4) different Avid Fflyer wing options.

Please search for "Different Wings" which will detail the specifics. You will see that there is a difference between adding an extension kit to the shorter spar Speedwing or Aerobat wing and using flat bottom ribs on a full length spar. Most notable will be the washout or wing twist. When adding a extension kit to a Speed or Aerobat wing which has been built to factory specs, the added length of the extension kit results in excessive, unnecessary washout which ends up hurting performance.

On the other hand, a long spar wing (usually called a STOL wing if undercamber ribs are 18" on center and a Heavy Hauler wing if undercamber ribs at 12" o.c.) built using flat bottom speed/aerobat ribs to factory specs will result in less washout. Actually, many (including me) build 'hybrid' or custom wings using Avid's flat bottom ribs 12" o.c. on long spars with less twist than the factory spec hoping for a faster cruise than the undercambered wing allows with little penalty in STOL performance and, of course, a stronger wing structure.

[klares 1]

I read the different wings thread and I think i get it. 

So the question is how did the builder go about it?

I got my info second hand that it had been built with aerobat wings but out to HH length, not really sure if it was with an extension or the way you describe.

 

Does anyone know a Gary Whittaker out of Tennesee by chance, he built the plane haven't had any luck getting ahold of him..

[EDMO 1078]

If the extensions were used, you might be able to see the rivets on the leading edge spar about 18" to 24" from last rib at tip of wing.

I don't think you should worry about how it was built - As Doug said, "It really don't add anything to takeoff and could slow cruise a little" in so many words.  But, It really don't matter much if extensions were used, IMO.  It was approved by Avid.

EDMO

Edited 30 Jun 2015 by Ed In Missouri

[birddog486 21]

Not to split hairs here but,

the short speedwing or the aerobat wing will have almost the same amount of washout as the STOL or HH wing if they're extended and were built by the manual.

 

The speedwing and aerobat wing are built (per manual) with 9' spars and have 1.5" of washout. The STOL or HH wing calls for 2" of washout in 12' which is the same 1/2" of washout per 3'

 

I built the extended Aerobat wing for my Avid and I've been considering building a different set of wings with little or no washout using the kitfox 4-7 rib profile.

 

Travis

[klares 1]

Not to split hairs here but,

the short speedwing or the aerobat wing will have almost the same amount of washout as the STOL or HH wing if they're extended and were built by the manual.

 

The speedwing and aerobat wing are built (per manual) with 9' spars and have 1.5" of washout. The STOL or HH wing calls for 2" of washout in 12' which is the same 1/2" of washout per 3'

 

I built the extended Aerobat wing for my Avid and I've been considering building a different set of wings with little or no washout using the kitfox 4-7 rib profile.

 

Travis

 

What prompted you to build the extended Aerobat wing, did they claim better stol at some point? How much better is the kitfox wing, anyway to quantify it?

I keep seeing that the highlander uses a wing like the Avid, anyone know how closely they are related?

[birddog486 21]

My kit was originally purchased as the Aerobatic speedwing. Over the years there were many complaints about landing these small planes so fast with the short wing and I decided to extend mine in hopes of getting it as slow as possible.

 

My plane is fairly heavy at 667# with a 912ULS hanging on the front and a stall speed at 48 MPH. The kitfox airfoil is superior to the avid speedwing rib with better slow flight characteristics and a higher top speed, I'm guessing with the kitfox rib this plane would fly 10mph slower and 10mph faster

 

Travis

[EDMO 1078]

I will jump in here and add a couple of things Travis didn't say:

     Dean Wilson used the modified undercamber Eppler ribs for a slow-flying light plane - Kitfox copied his design on the early planes - Dean put a large amount of washout there for slow flight and novice pilots to maintain control - However, this wing hits a "wall" at about 90 mph.  The Speedwing had a flatter bottom and did not perform much better.

     Harry Riblett did some testing on the ribs and discovered a bubble in the undercamber that forms and causes drag - same with the early flat-bottomed flaperons.  He designed a new rib and symmetrical flaperon that gave more cruise and less drag, with about the same lift, and Kitfox used it on the Model 4 and later wings, and changed the excessive washout from 1 3/4" to 1/2".

     There is some info in a couple of posts in "Files and Forms".

I don't know much about the Highlander, but some on here know about it.

EDMO

Best advise I can give:  If you have wings, fly and enjoy - If you don't, then build or buy - Then fly and enjoy!

If you want speed, get an RV, build a racer for the Reno Air Races, or buy a Lear Jet! 

Edited 18 Jul 2015 by Ed In Missouri

[LORENZ 9]

This thread killed my hopes of extending my speed wings on my MkIV

 

If I wanted the ultimate STOL capabilities would I be looking at the later Kitfox ribs or more of a Just Aircraft Super STOL set up which is probably untested on the Avid MKIV fuselage, in which case, I dont have the capability to make happen  

 

It sounds like I need a second airplane already..... Or a spare set of HH wings. Im guessing it's more of a hassle than its worth to swap wings back and forth than its really worth.

Edited 22 Dec 2015 by LORENZ

[EDMO 1078]

If you are just looking for STOL and don't care about going fast, the longer Kitfox 1,2,3 wings will do even better - the excessive washout on the early wings will give you better low-speed control with less chance of stalling.  You would have to probably modify your Avid struts to fit some of the Kitfox wings, or modify their struts to fit your Avid fuselage, as they have a different fitting there. 

I haven't looked at your location, but if you want to haul a set of Kitfox wings, flaperons and struts for a Kitfox 3 from St. Louis, then I have them.

EDMO

[akflyer 1427]

I flew a buddies extended speed wing and it performed as good if not better than my HH wing.  I liked the feel of it as it was lighter on the roll input than my HH wing.

[LORENZ 9]

If you are just looking for STOL and don't care about going fast, the longer Kitfox 1,2,3 wings will do even better - the excessive washout on the early wings will give you better low-speed control with less chance of stalling.  You would have to probably modify your Avid struts to fit some of the Kitfox wings, or modify their struts to fit your Avid fuselage, as they have a different fitting there. 

I haven't looked at your location, but if you want to haul a set of Kitfox wings, flaperons and struts for a Kitfox 3 from St. Louis, then I have them.

EDMO

Im in San Diego.

Are they finished with good ethinol safe fuel tanks?

[EDMO 1078]

If you are just looking for STOL and don't care about going fast, the longer Kitfox 1,2,3 wings will do even better - the excessive washout on the early wings will give you better low-speed control with less chance of stalling.  You would have to probably modify your Avid struts to fit some of the Kitfox wings, or modify their struts to fit your Avid fuselage, as they have a different fitting there. 

I haven't looked at your location, but if you want to haul a set of Kitfox wings, flaperons and struts for a Kitfox 3 from St. Louis, then I have them.

EDMO

Im in San Diego.

Are they finished with good ethinol safe fuel tanks?

I don't know what kind of tanks they are, except one in each wing, but the plane just finished a condition inspection before the engine quit for lack of oil.  It had about 170 hours on it. The wings were finished and had the Kitfox plastic leading edge and drooped tips - I heard something inside of one of them and decided that the fabric needed to be removed for a complete wing inspection - I have only cut two patches out of them to hang them up and found one detached false rib so far.  They would need recovering.

EDMO

Well, I forgot that the hanger tails are all broken on one wing - would have to be repaired - but that's not a big deal since they are not covered.

You probably don't want them now....That's OK.  I will keep them until someone wants them as is, or I get my plane finished so I have time to work on them.

Maybe you can find some wings in CA - Check with C5E Joey.

EdMO

Edited 24 Dec 2015 by EDMO