PDA

View Full Version : Not another stretched pacer question.....



Txtaildragger
08-09-2017, 08:33 PM
Good evening everyone,

I'm stretching a pacer fuselage......I'd like to find out the recommended place to cut and rebuild a new tail to my desired length( looking to add 24"). By the searching I've done I see the possible places to cut are directly after the baggage compartment....if anyone has any close up pics of the new attach points I'd sure like to see them..........any pertinent info would be greatly appreciated.

Jim
08-09-2017, 08:59 PM
Hi,

cappt posted some very interesting reading by Blanton and his V6 STOL in post #24 at http://www.shortwingpipers.org/forum/showthread.php?11849-Ferguson-taildragger-conversion Might be some about where you're headed.

Txtaildragger
08-09-2017, 09:24 PM
Thanks Jim, I'll take a look!

Stephen
08-10-2017, 02:19 AM
Search Super Pacer (Bushmaster) I posted a series of pictures in March that shows where the splice in the fuselage is done. Yes, it is aft of the baggage compartment. Bushmaster calls for 22.5 inches although, I've read about people adding up to 30 inches. Are you lengthening the wings?

Txtaildragger
08-10-2017, 07:04 AM
Stephen,

I will be building 63" cord 35' D&E Riblett wings. As far as the fuselage extension, I'm still learning the numbers on determining how to add what and where. I THINK I'm going to change the AOI a few degrees, still not sure though.
I'm being very cautious and trying to gather all the information I can to eliminate me going into demo mode on the fuselage and really screwing something up!
I'll check out those pics you posted.....thank you!

Stephen
08-10-2017, 09:11 AM
This will be a fantastic airplane. How will you build your ribs?

You would benefit from a set of Bushmaster drawings as a guide. Check out our thread "Looking for Bushmaster drawings" you can get a CD with most of the drawings.

Txtaildragger
08-10-2017, 09:30 AM
The ribs are hydroformed by D&E. Being this is a E/AB build I'm very interested in learning all available options. I'll definitely look for that CD. I have no problem taking guidance and learning from y'all!

Stephen
08-10-2017, 01:23 PM
The ribs are hydroformed by D&E. Being this is a E/AB build I'm very interested in learning all available options. I'll definitely look for that CD. I have no problem taking guidance and learning from y'all!

Post some pictures so others can see how you are doing your project.

Curt has CD's and is only asking for a donation to this site. Also, Steve P will post the drawings here for members. I think the CD will be high resolution for large format printing.

Txtaildragger
08-10-2017, 01:41 PM
I'll get some pics up today. Not much to show yet but just the fuselage and other parts scattered all over the shop!

Txtaildragger
08-10-2017, 06:54 PM
Since my computer skills are lacking for putting current project pictures on the thread I have a wing question.........Is wing loading the determining factor for choosing the total wing length.........or is it just that darn hangar door width?

Don D
08-11-2017, 09:34 PM
Stretched mine 23". Hammered my wing ribs from .025 2024 t3. 2 hours per rib.

Stephen
08-11-2017, 10:47 PM
Since my computer skills are lacking for putting current project pictures on the thread I have a wing question.........Is wing loading the determining factor for choosing the total wing length.........or is it just that darn hangar door width?

Building a plane that does not fit into it's space is not a good idea.

Wing surface area (thus wing loading) has a big effect on performance. I stared out 35 years ago with a 29 foot wing span Tri Pacer with Madras tips. Then I spliced the spars going to a 33 foot wing span under the Ferguson wing. The plane had a lower stall and approach speed but little change in cruise. It flew like a Pacer. All good. Now I have a 37 foot wing span with the Bushmaster mod and I have an even low stall and approach but I lost some cruise speed. Other differences are less measurable. The plane flys at much lower RPM's but, remains on the step for cruise. It flys like a Cub, only faster. So increasing wing span and adding SA has significant effects. Cruise speeds, stall speed and basic flying characteristics. Some are tradeoffs.

Stephen
08-11-2017, 10:50 PM
Stretched mine 23". Hammered my wing ribs from .025 2024 t3. 2 hours per rib.

Any picters of your rib work?

Txtaildragger
08-12-2017, 09:23 AM
Hammered your own ribs? Thats really neat, Id sure like to see a pic of those…….As for the wing length, I appreciate the explanation provided. Im stretching out to 25". I have no facts to back up why I'm using a 25" extension. Kinda figured after everything is said and done if needed Ill adjust the CG by adding inches to the engine mount, although i kinda think the controllable pitch weight may allow me with just using a zero thrust Maule mount……………..Just thinking out loud here.

Don D
08-12-2017, 07:41 PM
Flanging lightning holes is the hardest part. 23" is perfect stretch. Use the TLAR method. You can get Carlson extrusions and build truss type ribs which is what I would do if we're to build another plane. Sorry my pic's were before digital. Get Tony Bengillis books. They explain how to really build airplanes.

Txtaildragger
08-12-2017, 07:58 PM
Roger thar Don! I'll check out his books.

Southern Aero
08-19-2017, 11:09 AM
Hammered your own ribs? Thats really neat, Id sure like to see a pic of those…….As for the wing length, I appreciate the explanation provided. Im stretching out to 25". I have no facts to back up why I'm using a 25" extension. Kinda figured after everything is said and done if needed Ill adjust the CG by adding inches to the engine mount, although i kinda think the controllable pitch weight may allow me with just using a zero thrust Maule mount……………..Just thinking out loud here.

TX

Another option is to modify the original mount to a zero down thrust (take out the 3.75 degrees down) but leave the right thrust in it. OR you will need more fin offset or some form of rudder trim. Your choice of 25" is close enuff to bring your project in line with the other Piper long wing fuselage lengths...... which is the whole idea anyway. I used 24". I have heard of everything from 22 to 36. Obviously the longer you extend aft the more you must compensate forward. If you go with a constant speed prop you may be close in your balance issue. Unless you follow a previous conversion exactly, best way might be to save your engine mount to last and adjust length accordingly. With so many changes that can be made in the conversion it can be hard to calculate CG. I would suggest to adjust mount to most adverse forward CG condition of low fuel, single pilot and no cargo. FWIW

Txtaildragger
08-19-2017, 03:03 PM
I hear what your saying about the engine mount stuff...... Only thing is I'm going to be running a 360. Like you said, it's something I'll have to deal with when it's time weight the bird and modify accordingly. As far as the zero thrust, we'll I figured I'd build in a trim tab for the rudder.........the whole rudder offset modification or getting the precise engine mount angles has me scratching my head with building a jig.

Gilbert Pierce
08-20-2017, 08:58 AM
Look at Steve's Aircraft rudder trim system.

Steve Pierce
08-20-2017, 04:51 PM
So what is zeroing the thrusting going to do with the angle of incidence on a Pacer?

Txtaildragger
08-20-2017, 06:54 PM
That is what I'm wondering.........With my build plan I decided to leave the AOI alone. How exactly does building the vertical stabilizer off center affect a zero thrust line? Is a Maule vertical stab off center?

Southern Aero
08-20-2017, 11:41 PM
So what is zeroing the thrusting going to do with the angle of incidence on a Pacer?


Hi Steve,

Nothing, don't quite follow what your axing.......

??

Steve Pierce
08-21-2017, 06:11 AM
I know what the zero thrustline does on the Super Cub but question what it would do on a Pacer?

stevesaircraft(Bri)
08-21-2017, 12:54 PM
https://uploads.tapatalk-cdn.com/20170821/4fbd666c6f841c829ad94722521e61f7.jpg

This is the Darrenger.... It was built a few years back now... it is stretched, cabin raised 2 inches, modified Taylorcraft airfoil, Cessna 172 flaps and tracks and 0-360 with a zero thrust line custom mount... I have never rode in it but those I know that have say it flies real nice and it seems to perform pretty good...

The trust line being at zero works... but there are so many other mods it is hard to say exactly how much of a difference it made... but that is the beauty of experimental...

Brian


Sent from my iPhone using Tapatalk

Southern Aero
08-21-2017, 04:24 PM
I know what the zero thrustline does on the Super Cub but question what it would do on a Pacer?

Would do same thing but don't know of it being done on a stock Pacer, just a stretch. ............. Performance "enhancement" ....... Shortens ground run slightly, improves cruise a little and adds a slight amount of ground/prop clearance. ..... Was Pipers "auto trim" feature for their high lift section I guess. You will have to use a little more down trim with it zero.

TX was asking if Maules have fin offset and answer is yes......... Maule, Citabria, Scout, Decathlon, others. I do like Steve's Aircraft rudder trim idea..... keeps you from having to "tweak" the top of the fin on the Pipers. Much better than adding a trim tab.