Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Mar 11, 2011, 03:10 PM
Registered User
4stripes's Avatar
Canada, ON, Burlington
Joined Jan 2009
2,894 Posts
Discussion
Hobby Topgun 90mm L-39 in DDR markings ready for flight!

The Hobby Topgun L-39 is a very nice 90mm foamy. My dad deserves all the credit for details and cockpit and it is our best EDF yet. The two cockpits require extra effort as they are too large to ignore. The upgrade from parkflyerplastics required heavy modifications to make more scale but the clear canopy is a much better outline than the stock one (The exterior frames are in a better position). The wings are reinforced with carbon fiber and alloy arrow shafts. The stock landing gear legs have been modified to make them shorter. I've used some inexpensive FLYFLY clone air retracts from HK and the servos are HXT900. Flaps were added to improve T/O rotation and reduce landing rollout (worked well on my F-86). The final weight with 6S 5000mah 45-90C Nano-tech battery is 3.08kg (about the same as my F-86 and F-16). The fan is a hodge podge of parts. Freewing fan, Haoye shroud lined with plastic to reduce inside diameter and Turnigy Typhoon 500H 1800kv motor. The 38mm motor diameter forced me to use the Haoye shroud but I didn't like the fan as it drew way too many AMPS. The Freewing fan is a smaller diameter so the shroud inside diameter had to be filled to reduce the clearance. Hardly worth the effort as a stock Freewing motor/fan will produce similar thrust.
We chose the DDR (East German) markings as they used a similar camo scheme that the plane comes with. All large markings and cockpit instruments are photographs printed on photo paper. The smaller markings were hand painted. We also added a rudder (as we did on our F-86). All things considered this is a better product than the F-86. The biggest improvement is the landing gear struts are beefier and the flying surfaces are also more solid.
Can't wait to fly it!
Cheers
4stripes is online now Find More Posts by 4stripes
RCG Plus Member
Latest blog entry: Some photos of the EDF fleet!
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 11, 2011, 04:04 PM
tom
tomme21's Avatar
USA, LA, Natchitoches
Joined Apr 2004
1,579 Posts
wow! just wow!
tomme21 is offline Find More Posts by tomme21
Reply With Quote
Old Mar 14, 2011, 03:09 PM
Registered User
kimhey's Avatar
nøtterøy, NORWAY
Joined Mar 2006
1,171 Posts
Very nice build!
kimhey is offline Find More Posts by kimhey
Reply With Quote
Old Apr 16, 2011, 07:52 AM
Registered User
4stripes's Avatar
Canada, ON, Burlington
Joined Jan 2009
2,894 Posts
HTG L-39 brakes

Finally got the L-39 gear working properly so I've added some gear up shots. This aircraft handles strong crosswinds very well with its wide stance. Our legs are shortened 1" as the stock are too long. We also added brakes to help stop the fast landings when there is no head wind. The brakes are small levers pivoting just above each main wheel. They are actuated by a fishing line pulled by the flap servos when flaps UP is selected after landing. I always use flaps for takeoff and landing so the brakes are OFF until needed. They really slow the plane quickly so landings made very far down the runway can still be stopped in time before going off the end. There is extra wear on the tires so I'll use them judiciously.
4stripes is online now Find More Posts by 4stripes
RCG Plus Member
Latest blog entry: Some photos of the EDF fleet!
Reply With Quote
Old Apr 16, 2011, 03:35 PM
Registered User
Baca's Avatar
Melbourne , Australia
Joined Jun 2006
326 Posts
Great job,congratulation,I love it.Thinking of L-39 myself. How is Mig progressing?
Baca is offline Find More Posts by Baca
Reply With Quote
Old Apr 16, 2011, 04:17 PM
Registered User
4stripes's Avatar
Canada, ON, Burlington
Joined Jan 2009
2,894 Posts
Mig slowed a bit with the better flying weather but will continue this spring. Have all the components stripped of the flakey silver paint. Tail upgraded with full rudder top and bottom. Flaps strengthened with thin plastic doubler to prevent warping. Landing gear and all components are ready to install.
The cockpit is progressing nicely. I think it will be as good as the F86 if not better with the upgraded gear legs.
Cheers
4stripes is online now Find More Posts by 4stripes
RCG Plus Member
Latest blog entry: Some photos of the EDF fleet!
Reply With Quote
Old Apr 16, 2011, 10:44 PM
Official Boat Bum
Eddie P's Avatar
United States, NV, Reno
Joined Mar 2000
7,083 Posts
Looks nice, the details add up to a great looking model. Great work on the brakes too.
Eddie P is offline Find More Posts by Eddie P
RCG Plus Member
Old Apr 17, 2011, 12:33 AM
skunkworks
Dark Angel's Avatar
United States, CA, Clovis
Joined Apr 2008
1,536 Posts
Awesome job on the build !!!!!!!!!!!!!!
Dark Angel is offline Find More Posts by Dark Angel
Reply With Quote
Old Apr 18, 2011, 01:46 PM
Registered User
United States, AL, Southside
Joined Jun 2006
35 Posts
Is this the one from Hobby King, it looks great! I flew in a real L39 last summer with a
Ex F15 pilot and it was the ride of my life! They build (refurb) and maintain these about 10 miles from my house. I would really like to have a rc version myself. Drue
Geurin is offline Find More Posts by Geurin
Reply With Quote
Old Apr 18, 2011, 02:39 PM
Registered User
4stripes's Avatar
Canada, ON, Burlington
Joined Jan 2009
2,894 Posts
Yes it's HK.
Very reasonably priced 90mm EDF. No reason not to have one!
4stripes is online now Find More Posts by 4stripes
RCG Plus Member
Latest blog entry: Some photos of the EDF fleet!
Reply With Quote
Old Aug 17, 2011, 09:29 PM
Registered User
4stripes's Avatar
Canada, ON, Burlington
Joined Jan 2009
2,894 Posts
HTG L-39 cockpit bracing.

Replacing the nose gear and wheels to the HTG Mig 15 alloy type was well worth it. Made many flights on grass with no issues. The plane is the best one I have for strong winds and cross wind type flying. The working rudder will easily keep it on the runway center line and does a beautiful knife edge! The only additional mod we made recently was to add two 1/4" wooden dowels to secure the very weak nose section to the fuselage. German EDF forums have a number of posts where the nose separates in flight from the weight of the battery in high G pulls. I've done many flights (+70) and I've noticed the paint starting to crack in the weak area. If you look, there are wire channels located exactly in the part where you would want more strength! the foam sides just below the rear part of the canopy will crack causing catastrophic failure if no additional reinforcements are made. The thin foam will not hold the weight of a large 5000mah 6S battery if too many G's are made. My wooden dowels are glued just below the canopy and into the foam block we added between the intake ducts (to smooth the airflow). My cockpit floor was cut to lie flat and is glued to what was the back edge of the cheater hole adding some extra strength and more room for the battery. Glad we found this weakness before it cost us an aircraft! Especially since it is one of our favorites...
Cheers
4stripes is online now Find More Posts by 4stripes
RCG Plus Member
Latest blog entry: Some photos of the EDF fleet!
Reply With Quote
Old Aug 18, 2011, 06:11 AM
Registered User
kimhey's Avatar
nøtterøy, NORWAY
Joined Mar 2006
1,171 Posts
4Stripes, thank you for sharing the info on the weak nose section. I will definately strenghten mine before next flight. I run 8s4000 batts/3200w, so I have probably been very close to seperation on quite a few occations


Kim
kimhey is offline Find More Posts by kimhey
Reply With Quote
Old Jan 27, 2012, 04:37 AM
Registered User
Prague, Czech Republic
Joined Aug 2010
52 Posts
do you use steering nose gear, or just using rudder???
pupik123 is offline Find More Posts by pupik123
Reply With Quote
Old Jan 27, 2012, 05:26 AM
Registered User
4stripes's Avatar
Canada, ON, Burlington
Joined Jan 2009
2,894 Posts
It has both rudder and steerable nosewheel. Very good ground handling even in strong crosswinds.
Cheers
4stripes is online now Find More Posts by 4stripes
RCG Plus Member
Latest blog entry: Some photos of the EDF fleet!
Reply With Quote
Old Feb 01, 2012, 01:26 AM
Registered User
Prague, Czech Republic
Joined Aug 2010
52 Posts
OK, thanks. one more question. is CG in manual book right, or do you use different one?
pupik123 is offline Find More Posts by pupik123
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Rave NEW L-39 Albatros From Hobby TopGun & AirShowRC! wingspan100 Foamy EDFs 415 Jul 04, 2014 11:11 PM
Cool New HET L-39 90mm by EJF.com AceMigKiller Electric Ducted Fan Jet Talk 700 May 24, 2014 03:00 AM
Sold Rc-Warbirds / Jet-Tengs New 90MM L-39 Ready For Reciever $1500 Shipped. FlyBoyTha1 Aircraft - Electric - Jets (FS/W) 3 Nov 10, 2010 12:18 PM
Sold Receiver Ready Wicked Powered 50mm Jpower L-39 and T-45 The Don Aircraft - Electric - Jets (FS/W) 0 Oct 10, 2010 06:50 PM