Go Back  RCU Forums > RC Airplanes > RC Jets
Reload this Page >

Scratch Built Jet

Notices
RC Jets Discuss RC jets in this forum plus rc turbines and ducted fan power systems

Scratch Built Jet

Old 09-14-2010, 08:13 PM
  #1  
JohnW
Senior Member
Thread Starter
My Feedback: (6)
 
JohnW's Avatar
 
Join Date: Mar 2002
Location: Lincoln, NE
Posts: 1,815
Likes: 0
Received 0 Likes on 0 Posts
Default Scratch Built Jet

Posting this for inspiration to anyone that is thinking about or in the process of scratch building a jet. Typical twin boom design, local group project, started in October 2009. Prototype flew in June of 2010, first “finished” plane flew in September 2010. Composite and foam/balsa build. Fuse is glass and booms are carbon/Kevlar sandwich. Carries about 130oz of fuel in three scratch built tanks in the wing. Wingspan is about 80 inches, plane weights 22.5lbs ready to fly with a P120, 28lbs on takeoff with full fuel load. Airfoil is fully symmetrical. Performance envelope is huge with the P120, stable in the air upside down as well as right side up, holds knife edge as long as you have fuel. Attached a few pics starting with very early plug stage to finished jet. - John
Attached Thumbnails Click image for larger version

Name:	Om33942.jpg
Views:	229
Size:	125.4 KB
ID:	1501026   Click image for larger version

Name:	Id96903.jpg
Views:	273
Size:	139.4 KB
ID:	1501027   Click image for larger version

Name:	Ou49750.jpg
Views:	237
Size:	126.9 KB
ID:	1501028   Click image for larger version

Name:	Mx23583.jpg
Views:	251
Size:	91.9 KB
ID:	1501029   Click image for larger version

Name:	Wn85682.jpg
Views:	572
Size:	113.6 KB
ID:	1501030   Click image for larger version

Name:	Xz54174.jpg
Views:	239
Size:	129.9 KB
ID:	1501031   Click image for larger version

Name:	Ml39158.jpg
Views:	208
Size:	135.3 KB
ID:	1501032  
Old 09-14-2010, 08:34 PM
  #2  
rcguy!
My Feedback: (69)
 
rcguy!'s Avatar
 
Join Date: Jan 2002
Location: Chesterland , OH
Posts: 2,842
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

Looks GREAT! Nice lines! Any chance of a kit someday?

Dave
Old 09-15-2010, 12:28 AM
  #3  
ps2727
 
Join Date: Feb 2003
Location: ft worth, TX
Posts: 493
Received 4 Likes on 2 Posts
Default RE: Scratch Built Jet

John,
Very nice work there. I know how much effort it takes to get that far with a new design.
Congrats on a nice looking sport jet!
Love the shot of the structure in the mold.

Paul
Old 09-15-2010, 07:32 AM
  #4  
Bob.R
My Feedback: (2)
 
Bob.R's Avatar
 
Join Date: Jun 2004
Location: Canyon Lake, TX
Posts: 789
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

Very nice work John. Like the intakes.
Old 09-15-2010, 06:06 PM
  #5  
JohnW
Senior Member
Thread Starter
My Feedback: (6)
 
JohnW's Avatar
 
Join Date: Mar 2002
Location: Lincoln, NE
Posts: 1,815
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

Thanks for all the kind comments.

rcguy, kitting has been considered, but there are several challanges to producing kits I haven't fully addressed.

-John
Old 09-15-2010, 06:57 PM
  #6  
rcguy!
My Feedback: (69)
 
rcguy!'s Avatar
 
Join Date: Jan 2002
Location: Chesterland , OH
Posts: 2,842
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

John,

Damn good looking jet for sure. Has a more "modern" look to it than other pod and boom offerings. Much more "USA" type lines.... I would consider an kit if you offered one even on a limited basis.

Dave Rigotti
Old 09-15-2010, 07:42 PM
  #7  
AndyAndrews
 
AndyAndrews's Avatar
 
Join Date: Feb 2007
Location: Little Rock, AR
Posts: 6,138
Received 4 Likes on 4 Posts
Default RE: Scratch Built Jet

You did a great job on it and it looks nice. But why another boomerang? Does you're boomerang offer anything better than the existing one out there? Wings glassed? Seriously, it really looks just like a Boomerang other than the front part of the fuse.
Old 09-15-2010, 08:00 PM
  #8  
rcguy!
My Feedback: (69)
 
rcguy!'s Avatar
 
Join Date: Jan 2002
Location: Chesterland , OH
Posts: 2,842
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

Nice Andy!
Rain on the dudes parade!
Sheesh!

Dave
Old 09-15-2010, 10:49 PM
  #9  
JohnW
Senior Member
Thread Starter
My Feedback: (6)
 
JohnW's Avatar
 
Join Date: Mar 2002
Location: Lincoln, NE
Posts: 1,815
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

Heh... I don't mind rain. Andy’s comment is relevant and I understand the criticism.

As to “different”, I think all planes look pretty much the same because aerodynamics dictates the shape. If I had made a sleeker sport jet, I’m sure the comment would have been it looks just like a Bobcat except the fuse is a bit different. While this plane has similar moments to an Elan, everything was designed fresh. I’ve put the two side by side and they actually look very different.

From a personal standpoint, I can take pride that I’m flying a plane of my design. I enjoy the challange of both designing and flying planes. All of my existing planes except one (Velox) were built by me and over 50% are my own design.

My individual cost was still lower than what I can get a Elan and a can make myself as many copies/parts as I want, whenever I want. This not only benefits me, but offered a less expensive entry to turbines to several others in on the project that don’t yet fly jets. Our club has a strong turbine presence, getting stronger every year with 100 members, of which I think seven have waivers and fly on a regular basis in the summer, and it will soon be more with this project. Truth be told, I was going to buy an Elan as a goof off plane last October to add to my turbine fleet, but several skilled pilots in our club that wanted into jets didn’t have the financial means to start, which convinced me to start this group project instead.

I believe it is built stronger than Elan’s I’ve seen without significant weight penalty, especially the booms which are a light but very strong carbon/Kevlar sandwich, similar to how I make pattern ship sides. I’ve seen Elan’s split booms on landings. You’d have to destroy this plane and everything in it to split these booms.

The airfoil is fully symmetrical (GOE459) and thicker than boomerangs I’ve seen. Doesn’t seem to impact the top end noticeably. I can’t prove it, but I’m pretty sure it should provide superior low speed performance. It is the same airfoil I use on my pattern ships.

Tanks are in the wings, keeping fuel load in line with the center of mass, which makes the most sense to me.

Due to time, wings/stab and all control surfaces are currently all sheeted foam. That might be resolved this winter if I have the time to make more molds.

-John
Old 09-16-2010, 02:23 AM
  #10  
Ravivos
Senior Member
 
Ravivos's Avatar
 
Join Date: Aug 2006
Location: Petah-Tikva, ISRAEL
Posts: 291
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

Hi John,
First things first - that sure is a nice plane you got there.
although it have some resemblance to other twin boom planes out there, i am sure that as for flying characteristics it is great.
i can totally relate to the "design my own" concept as for me, RC is more than just standing out there fiddling with those two little stick on my million dollar transmitter.

you said that you take great pride in flying your own design and you should, as there aren't that many like you out there.

can you share some of picture and information from the design and building process?
mainly aerodynamic consideration - Tail Volume Coefficient, Wind Cubic loading, balance and moments ect....

Raviv.
Old 09-16-2010, 07:10 AM
  #11  
i3dm
My Feedback: (51)
 
Join Date: Jun 2004
Location: Reut,Israel
Posts: 4,321
Received 10 Likes on 9 Posts
Default RE: Scratch Built Jet

Very nice ! do you plan on making kits ?
Old 09-16-2010, 11:05 AM
  #12  
grbaker
My Feedback: (29)
 
grbaker's Avatar
 
Join Date: Dec 2001
Location: La Porte TX
Posts: 3,536
Received 11 Likes on 10 Posts
Default RE: Scratch Built Jet

John,

You hit it out of the park on your first try!! (I'm assuming this is your first jet design)

No worries about weak internal structures here. Everything looks very well thought out and structures look robust. This one will take a lickin' and keep on tickin'!. Sheeted foam wing and stab are just fine, too.

Please keep us informed if you deide to sell kits.
Old 09-16-2010, 09:22 PM
  #13  
JohnW
Senior Member
Thread Starter
My Feedback: (6)
 
JohnW's Avatar
 
Join Date: Mar 2002
Location: Lincoln, NE
Posts: 1,815
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

While not my first plug/mold/composite project, you are correct that this is my first turbine design project. It also was the most technically challenging project to date. It is amazing how complicated a “simple” looking plane can actually be to design and build.

I didn’t save most of design calcs as they were mainly back of napkin in nature, but I still have the working drawings. Not a lot to see, but I attached screen shots of the main drawing that has the basic layout and some of the formers.

-John
Attached Thumbnails Click image for larger version

Name:	Bz78690.jpg
Views:	146
Size:	67.5 KB
ID:	1502117   Click image for larger version

Name:	Vq51913.jpg
Views:	120
Size:	30.8 KB
ID:	1502118   Click image for larger version

Name:	Uz69391.jpg
Views:	121
Size:	71.3 KB
ID:	1502119  
Old 09-17-2010, 09:34 AM
  #14  
H.Dale
My Feedback: (3)
 
Join Date: Feb 2003
Location: Jackson, MS
Posts: 537
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

John

Excellent job! I have been considering scratch building a jet but have never attempted making a composite. It looks like a daunting task from all I have been able to learn. I have modified a Bobcat (shown below) but would like to attempt to make it a one piece composite much like the other picture below. How hard would that be?

Hal
Attached Thumbnails Click image for larger version

Name:	Sq48270.jpg
Views:	156
Size:	82.8 KB
ID:	1502269   Click image for larger version

Name:	Id96286.jpg
Views:	165
Size:	122.6 KB
ID:	1502270  
Old 09-18-2010, 01:37 AM
  #15  
JohnW
Senior Member
Thread Starter
My Feedback: (6)
 
JohnW's Avatar
 
Join Date: Mar 2002
Location: Lincoln, NE
Posts: 1,815
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

Hal, making plugs/molds, working with composites, etc. isn't hard, but it does take a special skill set you must learn. I started making plug/molds about 5 years ago, so really not all that long ago. I started small, a cowl and some wheel pants, then a 2M pattern ship, and now this jet. I found the composites section on RCU very valuable as well as other sources such as the youtube videos of the B1 bomber build, etc. The largest challange is that plug/molds are a pay up front process. Making a plug/mold can be time consuming, but the reward is the parts build fast.
Old 09-18-2010, 03:33 AM
  #16  
cmjets
 
cmjets's Avatar
 
Join Date: Apr 2005
Location: Pontevedra, SPAIN
Posts: 1,706
Likes: 0
Received 20 Likes on 19 Posts
Default RE: Scratch Built Jet

Hi John:

Great job, but why you chose that plane, I think there are another beautiful models.

See my Bandit, Bobcats and Starjet.

Best Regards from Spain.

Carlos.
____________________________
http://cmjets.blogspot.com/
Attached Thumbnails Click image for larger version

Name:	Us54913.jpg
Views:	128
Size:	122.4 KB
ID:	1502781   Click image for larger version

Name:	Jf11610.jpg
Views:	128
Size:	93.7 KB
ID:	1502782   Click image for larger version

Name:	Bg92891.jpg
Views:	106
Size:	99.8 KB
ID:	1502783   Click image for larger version

Name:	Pi16554.jpg
Views:	126
Size:	32.7 KB
ID:	1502784  
Old 09-19-2010, 06:05 PM
  #17  
dave.windymiller
 
dave.windymiller's Avatar
 
Join Date: Oct 2004
Location: , UNITED KINGDOM
Posts: 96
Likes: 0
Received 1 Like on 1 Post
Default RE: Scratch Built Jet

Im going down a similar path with my first jet to keep cost down but its still far from flying.

Mig 1.44






Old 09-30-2010, 06:48 PM
  #18  
JohnW
Senior Member
Thread Starter
My Feedback: (6)
 
JohnW's Avatar
 
Join Date: Mar 2002
Location: Lincoln, NE
Posts: 1,815
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

Dave, that is a awesome looking project. Look forward to maybe catching some pics of it here when it is flying.

Carlos, very nice. I previously explained the motivation for choosing this type of plane, and now that I have put ~30 flight on it I can say it is a blast to fly. It flys a lot like a pattern ship... welll, a jet powered one anyway. Very neutral on the controls. The low speed aerobatic handling is better than I've seen on any other plane except thrust vectored models, i.e. very stable but can change direction quickly. Takeoff to a tight 1/2 loop going inverted down the runway the opposite way I've found quite amusing.
Old 09-30-2010, 07:09 PM
  #19  
RAPPTOR
My Feedback: (41)
 
Join Date: Dec 2001
Location: WEST PALM BEACH, FL
Posts: 1,727
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Scratch Built Jet

very kool ..how did you figure c/g..??
Old 12-16-2014, 06:10 PM
  #20  
GOGGLES PIZANO
Senior Member
 
Join Date: Jan 2005
Location: MESA, AZ
Posts: 262
Likes: 0
Received 0 Likes on 0 Posts
Default

I found this thread by accident....I love the modified might bobcat H.DALE.I would love to see more pics and detail if possible.looks awesome.thx.
Old 12-16-2014, 06:44 PM
  #21  
turbinebuilder
My Feedback: (5)
 
turbinebuilder's Avatar
 
Join Date: May 2008
Location: tucson, AZ
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Default

Good to know there are more scratch BUILDERS.Arfs are lot easier but there is no warm and fuzzy feeling after ASSEMBLING them.Anyway here's mine.
Attached Thumbnails Click image for larger version

Name:	100_2145.JPG
Views:	753
Size:	1.19 MB
ID:	2055706   Click image for larger version

Name:	100_2146.JPG
Views:	753
Size:	1.41 MB
ID:	2055707  
Old 12-16-2014, 06:44 PM
  #22  
erbroens
 
erbroens's Avatar
 
Join Date: Nov 2003
Location: Curitiba, Parana, BRAZIL
Posts: 4,271
Likes: 0
Received 6 Likes on 6 Posts
Default

Great work, congrats! To me seems wise being conservative on the airplane design as a club project..guaranteed fun for everyone.

This are two airplanes I designed some years ago thar are still around and are a lot of fun too.. The Hotcat and the JM-1


Attached Thumbnails Click image for larger version

Name:	hc.jpg
Views:	746
Size:	41.8 KB
ID:	2055708   Click image for larger version

Name:	jm1.jpg
Views:	691
Size:	44.5 KB
ID:	2055709  

Last edited by erbroens; 12-16-2014 at 06:53 PM.
Old 12-16-2014, 08:26 PM
  #23  
sidgates
My Feedback: (2)
 
Join Date: May 2002
Location: Denver, CO
Posts: 1,425
Likes: 0
Received 0 Likes on 0 Posts
Default

Below is my scratch built F-94C. Currently waiting for test flight. 82.5" long, 76" span, est. 22lbs. White will be replaced with aluminum after test flying which may be awhile do to winter weather in Denver. Build pictures available on my web: http://www.sidgates.us/HOBBIES/PROJECTS.HTM

Attached Thumbnails Click image for larger version

Name:	F-94C At Jefco Meeting.jpg
Views:	715
Size:	862.1 KB
ID:	2055742  

Last edited by sidgates; 12-16-2014 at 08:30 PM.
Old 12-16-2014, 08:27 PM
  #24  
DiscoWings
My Feedback: (76)
 
DiscoWings's Avatar
 
Join Date: Aug 2004
Location: Baton Rouge, LA
Posts: 2,715
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by turbinebuilder View Post
Good to know there are more scratch BUILDERS.Arfs are lot easier but there is no warm and fuzzy feeling after ASSEMBLING them.Anyway here's mine.

that looks very cool.
Old 12-17-2014, 07:28 AM
  #25  
mick15
 
mick15's Avatar
 
Join Date: Apr 2002
Location: Essex, UNITED KINGDOM
Posts: 1,958
Likes: 0
Received 1 Like on 1 Post
Default

Here's my contribution to the scratch built. Sorry it's a twin boomer! It is scale though.
Attached Thumbnails Click image for larger version

Name:	IMG_4892.JPG
Views:	72
Size:	51.7 KB
ID:	2055807   Click image for larger version

Name:	IMG_4895.JPG
Views:	77
Size:	9.9 KB
ID:	2055808   Click image for larger version

Name:	IMG_4896.JPG
Views:	89
Size:	10.7 KB
ID:	2055809   Click image for larger version

Name:	IMG_4897.JPG
Views:	82
Size:	8.1 KB
ID:	2055810   Click image for larger version

Name:	IMG_4898.JPG
Views:	95
Size:	7.9 KB
ID:	2055811   Click image for larger version

Name:	IMG_4900.JPG
Views:	102
Size:	54.0 KB
ID:	2055812  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.