Jerry Burr
MEMBER
Sedro Woolley, Washington.
Wanted a set of those ugly, heavy, no good Demer tips. Madras or what ever name they go by. Got some in the back yard you want to get rid of, let me know. Thanks. Jerry.
Demer tips
- Thread starter Jerry Burr
- Start date
Steve Pierce
BENEFACTOR
Graham, TX
I've got a pair Jerry. On is cracked where it appears the two halves go together. I will take some pics and send to you.
Stocky
Registered User
Anchorage, AK
Extended Wings
OK guys here it goes.
I found, and bought a set of unused Madras tips complete with all the hardware and associated paperwork. A fella I met out at birchwood had been storing them in his hanger. I decided a little while back when I got some damage to a bow on my -12 due to hanger rash, now would be the time to convert. When I started to look around at other airplanes on Lake Hood, I thought I would do some measuring to see how much wing area I would really gain. Here is what I found in measurments from the last full rib (next to the aileron) to the outside edge of the tip. (These are all approximations, they seem to vary by 1/2 inch or so)
Stock wingtip 28"
Demers (Madras) per STC 12"
Some other extension plus Demers (Madras) 24"
Much to my surprise, by my rough calculations, putting on the Madras booster tip as per STC causes a total loss of approxiamtely 9-10 square feet. Granted that a stock, cub wingtip isn't a high lift sort of airfoil, but I'm pretty sure it creates some lift. With the unknown extension, the wing square footage is about the same as a stock wing except it is a true airfoil most of the way out.
Now here comes the point of this post. Who holds an STC that would allow me to add that extra 12" of wing on, before I install the tip to regan that area? This is a one time shot, because the Madras STC has you cut the cap strip tangs at the end of the spar. Most of the extensions I've talked about with people, have these strips bent outward to accept a flat piece of aluminum and therefore a new rib and butt rib. If I cut them off, they're gone.
The airplane was recovered about ten years ago, so a full teardown to extend the ailerons and add flaps is not desired right now. I've read the discussions about the pro's and con's of these tips and extensions without changing the flight controls, and have decided to do it. I'm just looking for the knowledge on how? The extension portion that is?
Any help is greatly appreciated, the couple of guys I've found via the FAA registry and internet search that had this combination were not really too interested in helping me out.
Thanks,
Tim
OK guys here it goes.
I found, and bought a set of unused Madras tips complete with all the hardware and associated paperwork. A fella I met out at birchwood had been storing them in his hanger. I decided a little while back when I got some damage to a bow on my -12 due to hanger rash, now would be the time to convert. When I started to look around at other airplanes on Lake Hood, I thought I would do some measuring to see how much wing area I would really gain. Here is what I found in measurments from the last full rib (next to the aileron) to the outside edge of the tip. (These are all approximations, they seem to vary by 1/2 inch or so)
Stock wingtip 28"
Demers (Madras) per STC 12"
Some other extension plus Demers (Madras) 24"
Much to my surprise, by my rough calculations, putting on the Madras booster tip as per STC causes a total loss of approxiamtely 9-10 square feet. Granted that a stock, cub wingtip isn't a high lift sort of airfoil, but I'm pretty sure it creates some lift. With the unknown extension, the wing square footage is about the same as a stock wing except it is a true airfoil most of the way out.
Now here comes the point of this post. Who holds an STC that would allow me to add that extra 12" of wing on, before I install the tip to regan that area? This is a one time shot, because the Madras STC has you cut the cap strip tangs at the end of the spar. Most of the extensions I've talked about with people, have these strips bent outward to accept a flat piece of aluminum and therefore a new rib and butt rib. If I cut them off, they're gone.
The airplane was recovered about ten years ago, so a full teardown to extend the ailerons and add flaps is not desired right now. I've read the discussions about the pro's and con's of these tips and extensions without changing the flight controls, and have decided to do it. I'm just looking for the knowledge on how? The extension portion that is?
Any help is greatly appreciated, the couple of guys I've found via the FAA registry and internet search that had this combination were not really too interested in helping me out.
Thanks,
Tim
Steve Pierce
BENEFACTOR
Graham, TX
TJ has the paperwork in his photo gallery for bending the capstrips up. The Pacer I just bought with a friend has them with the cut of spars and there is a Tri-Pacer here with the bent up spar cap. Big difference in wing area as you noted.
behindpropellers
Registered User
NE Ohio
Jerry Burr said:
I thought I had PM'd you about a month ago on a set I saw on ebay....
Steve's Aircraft (Steve)
FRIEND
White City Oregon
The Madras (Demer) tips, manufactured in Madras Oregon, required the spar caps to be removed. That STC is currently dormant because Ace Demers passed away. The Plane Booster tips that required the caps to be straightened to give an extra 9 " of wing was bought by Cub Crafters. Cub Crafters has since changed the profile of the tip so if you damage one, you also have to replace the opposite one at the tune of $650 each.
Steve
Steve
Fortysix12
Registered User
RanchAero Grand Vista, Brooksville
Do they work. And just what is the advantage or advantages.
Steve Pierce
BENEFACTOR
Graham, TX
Anybody have a Demer/Madras left wing tip sitting around? Have a Pacer with a damaged one, can be fixed but will be a pain.
mike mcs repair
Registered User
chugiak AK
back when i was young and skinny... and nothing was impossible... but maybe not cost effective... a touch of tinfoil to form it and some fiberglass.. good to go!!
txfirefighter628
Registered User
Brownwood, TX
Havent been on the threads for a while, been studying for my A&P test, but I have a set of Madras tips off my PA-12, not sure if they will fit a PA-20 wing though. I think Chris has a set off a colt project also if you still need one.
Steve Pierce
BENEFACTOR
Graham, TX
We fixed the damaged tip. Thanks.
Demer tips still available?
Any chance you still have the demer tips? Need to replace the right one on my PA-12
Any chance you still have the demer tips? Need to replace the right one on my PA-12
skywagon8a
MEMBER
SE Mass MA6
What condition is your right one in? It's only fiberglass......fixable. I'm not a fiberglass person, but I would not be afraid to tackle it if it were mine.
Its in pretty rough shape. Doubt it's fixable.
Yes possibly. We bought Dakota tips but realized we're going to have to replace outboard ribs and modify the aileron. I'm not a huge fan of the drooptips, but we might be stuck with them now. Where are you located? Can you send pics?
gntw
SPONSOR
Ft. St. John BC Can.
Was wondering why the Dakota tips wouldn’t fit on I just ordered a set from Dakota to replace demer tip because the owner of the plane doesn’t like them and wants to change. Can’t see why they won’t fit
It looks to me like with the droop tips (I'm not actually sure if mine are madras or other to be honest. Do you know how to tell? ) the 2 ribs are shorter than the Dakota cub tips so we have to replace them with longer ones. Then modify the aileron so it goes straight into that junction rather than curving forward like it originally was to match up with the bowtip wing.
supercub1999
Registered User
Google search comes up with lots of pics of tips, not sure how many different kinds of droops there were made, here is link https://www.google.com/search?q=mad...Ag&cshid=1613019034175&biw=768&bih=1024&dpr=2
Attachments
supercub1999
Registered User
You have what are called Plane Booster tips. Attached the .pdf stc manual link. If you compare your wing tip to a Madras you will notice the Madras excessive droop from the leading edge back to the trailing edge of the tip, your Plane Booster tip does not have that droop, they are a strait edge along the bottom of the tip, no droop. The float has Madras tips, the Super Cub has Plane Booster tips like yours
https://www.supercub.org/forum/attachment.php?attachmentid=5393&d=1329012675
Attachments
Last edited:
gntw
SPONSOR
Ft. St. John BC Can.
ok I was just checking ours has full length ribs and ailerons are already squared off thanks for the reply
You have what are called Plane Booster tips. Attached the .pdf stc manual link. If you compare your wing tip to a Madras you will notice the Madras excessive droop from the leading edge back to the trailing edge of the tip, your Plane Booster tip does not have that droop, they are a strait edge along the bottom of the tip, no droop. The float has Madras tips, the Super Cub has Plane Booster tips like yours
https://www.supercub.org/forum/attachment.php?attachmentid=5393&d=1329012675
Ok thanks! I've also read that cubcrafters has modified the design slightly meaning I couldn't just buy one side. Do you know if this is true?
