Maiden Flight HSD L39 120mm EDF 12S

The day finally came to make the maiden flight of my L39 from HSD Jets UK. Adrenalin was flowing but I was not too nervous or over confident, triple Checks prior to arriving at the field and a good once over on the field put me in a good frame of mind. All the surface throws were set to the manual and the CG markings on the plane and manual were cross checked.
On the day of the maiden flight the wind was coming from the East at 5mph. Not the best direction for our field and a maiden flight as there is a 1.5m height difference from the west end of the strip to the East end meaning a tricky down hill landing. You will see in the video all 300m of the strip was used to get here down and the wheel brakes were used to good effect to bring here to a dead stop on the last blades of grass.
The L39 required 30% (3mm) of up elevator elevator trim dialling in and 10% of right aileron trim. She was very twitchy on the elevator but manageable when I dropped the rates to the minimum setting of 65% and 40% Expo.
Thank you to Keith Howlette for the excellent video footage, Photos and compilation of the final video here with.
Many thanks also to David Taub at HSD Jets UK for his support and great service throughout the choosing and purchase process of this wonderful model.
I hope you enjoy the video and thank you for watching this and my other related videos to the HSD L39 EDF

[@SeekingTheVerdants]

Beautiful jet there. I really like the matte finish too. Very smart thing you did keeping it up high to dial everything in like you did. I hope everything is still fine with her. Many happy flights.

[@All_things_RC.]

thanks for your comments and yes she is still going good with over 100 flights logged. Great model and would highly recommend.

[@lmramos44]

CG looked off. That nose kept seeking the ground. Thanks for the video.

[@All_things_RC.]

Thanks for your comments. I agree this model is still nose heavy however, the only way to move the CG back now is to add weight at the tail which I don't really like doing. When the L39 is inverted I need only the slights touch of down elevator to keep here level. This doesnt have to be held, she will stay level once the nose attitude is slightly up. As I am so close I think to leave the CG alone and get use to pulling a touch of up in to stop the nose digging in on the turn.
After all a nose heavy plane will fly but a tail heavy plane?
Thanks for your feed back.

[@redalrt4]

It sounds amazing!

[@markdavis7397]

Thanks for posting, I am putting this plane together now. You mean it was twitchy on the elevator at 15mm? I have about 12mm low throw and 15mm high throw, and I was going to start on low (I typically stick with low throws for first several flights).

[@All_things_RC.]

Hi Mark my comments on the video was as the maiden/trimming flight unfolded. At this point I was un aware of the flap elevator mix and servo speed problem. What was happening was a none linear movement between elevator stick and elevator movement. The twitchy feel I commented on was actually the slow response between the stick position and elevator movement. For example I would pull back on the elevator stick to climb because of the slow elevator movement I used allot more up on the Tx than I required. When the elevator on the plane caught up to the stick position I had too much elevator. I then pushed the stick forward to go back to neutral flight the final position of the elevator stick mean the model pasted neutral flight and went into a dive. We are talking less than a second on the linear difference making the model feel twitchy.
I now have my L39 set as you mention 15mm high rates 12mm medium rates and 10mm low rates with 35% expo across all three. I use high rates when landing middle rate for scale flight and low rate when flying fast.
I hope this helps

[@stevenvater8720]

Very lucky to have a flying site like that

[@All_things_RC.]

Thanks Steve Its a great site we have been there coming up to 30 years now. We have a good relationship with the local village and surrounding farms but we never take it for granted.

[@stevenvater8720]

@@All_things_RC. thanks for reply let's hope awful weather improves and we can all get flying. Lovely EDF by the way like it

[@laurensmith2421]

Hi my husband has bought this plane put it altogether has 12s batteries but when he went to take off there was no power when we bought the plane it had no instructions and the shop haven’t sent them was this something you experienced with ur L39

[@All_things_RC.]

Hi Lauren I did have a similar problem with an HSD Viper 105mm EDF but not the L39. I assume you are putting two 6s batteries together to make a 12s? If this is the case these must be matched. I have found the best way to pair lipos (for example 2 x 6s) is to preferably have two from the same manufacture but a MUST is to have the same chemistry for each battery (Lipo to Lipo or Graphine to Graphine etc), the C rating MUST be the same (60C to 60C), the mah capacity MUST be the same. Also at the end of the charge I will look at the internal resistance of my lipos and pair batteries with the closest internal resistance.
As all EDFs the C rating is critical and preferably 60C or above should be used. Batteries with a good number of cycles on them (well used) will also lower the performance.
Hope this helps.

[@sendit_rc]

Calibrate esc if you don't have any power.

[@drmrjon]

Have you found that the foam body looks like popcorn when exposed to the sun??

[@All_things_RC.]

Only in the Cockpit area, however I do cover all my models on a sunny day at the field.

[@tomling9310]

Hi mate. How do you find the power set up on this compared to your Viperjet? Looks much better? Thanks Tom.

[@All_things_RC.]

Tom the 120mm EDF's perform the best in my opinion. HSD need to do some work on the 105mm range before I would consider buying again.

[@rckeith]

Thanks, Pete, looks good.

[@josemariamoro3009]

This Manufacturer is not responsible for the problems that arise in its models. I launched a super electric Ferrari Viper with a 105 mm turbine a few days ago, the turbine stopped due to a failure in the ESC (Variator) and they say that I take care of the damages. Incredible the little seriousness !!!

[@All_things_RC.]

Hi Jose I found my distributor (HSDJET UK) very helpful and they soon got me back into the air again. My issues were purely brought on by my intervention. Sorry to here about your issues, maybe your distributor can help rather than dealing with HSD direct?

[@Maggifix2]

Hi did you usy original point of gravity?

[@All_things_RC.]

I fly with the CG on the very rearward point shown in the manual. I need only a gentle touch down elevator when it is inverted.

[@FENIXRC]

Buen vuelo like 👍🏼 saludos ✈

[@christelb5052]

hello, has HSD also other colour scheme"s? enough power this plane? thx

[@All_things_RC.]

Hi Christel at the moment not for the EDF version but there are two schemes for the Turbine version.

[@christelb5052]

@@All_things_RC. has he enough power ? flight time? thx

[@All_things_RC.]

@@christelb5052 power is good for scale flight but not as fast as a spots jet. Flight times are 3m 30s to 4m depending on throttle use when using a 5000mah lipo

[@christelb5052]

@@All_things_RC. thank you

[@jeffjackson6358]

There’s also Breitling scheme. And none of the decals come pre-applied.

[@mc...square6510]

I c u have 20/20

[@comtzu50]

A one mille away video is pointless video…cheers!!

[@All_things_RC.]

The camera hasn't done me justice trust me it was not 1 mile away. Having said that a maiden flight should be conducted hi especially when conducting stall tests. flap tests, etc. One mistake is the best way to approach a maiden just in case anything goes wrong.