A bigger DH Venom

Painting nearly complete.
 
A bit unusual as just the windscreen is removable as battery hatch.
It is a bit heavier than I originally estimated at 436g less the tip tanks. They will be left off until after its maiden.

Painting and the decals now complete.
 
It just needs a light spray pf clear acrylic to 'harden' the Depron surface a bit.
I was getting a bit concerned at its weight so I have modified the battery box so it can accept a 1300mAh 4s, a 1000mAh 4s or the original intended a 1500mAh 3s. 

Nice paint.  Indeed a very nice looking model. A few questions:
What kind of paint are you using?  
How are you applying it?
How much weight does it add?

The bigger Venom is now complete and ready to go.

Although a bit heavier than I intended at 450g I expect it will fly quite adequately on 3s although I can use a 4s if necessary.

jon
I am using SCOLA acrylic paint, It is water based so does not attack foam but fully waterproof when dry. It is applied with a brush and easy to clean, provided you don't let the paint  on the brush dry first!
It is quite a thick paint so only one coat, 
The decals are printed on ordinary printer paper, very carefully cut out and stuck on using a glue stick.
The total weight of paint + decals + a light spray of clear acrylic lacquer is about 15g.

If I ever have to significantly rebuild it I would move the EDF forward 50cm and redo the inlet duct in order to make it easier to achieve the CofG. At the moment everything has to be squashed into the nose area as far forward as it will go. 

Oops! Lets say 50 mm.
I just had to see what it looks like with the tip tanks on.
 
They are only just spot glued on so easy to remove.
 

I did sort of maiden the bigger Venom yesterday as it was unusually calm.
It was a sort of maiden as the CofG was a bit too far aft making control almost impossible. After an enourmous PIO more by luck than judgement I managed to arrange the end of the PIO to be close and parrallel to the ground to make a "firm" landing.. Only damaged the nose cone.
It has now been replaced with a specifically "heavy" version nose cone..
I might also 'rob' the gyro Rx out of the Hawker Hunter. It reacts much faster than I can.  .  

I added some nose weight and it flew. surprisingly fast and terribly twitchy. Two circuits n o real problem but just before the landing flare it dropped it nose and came to a sudden halt  in the long tufted grass. Cracked the tail booms but an easy repair.

I have a suspicion that some of the twitchyness is down to the proximity of the tail plane to the exhaust stream.
 
During a pitch up the tailplane enters the exhaust stream and vice versa. Not good for what is already questionable stability.
When I built the Venom I did not give the boom a sufficient up angle. It is really quite noticeable. Doh!
 
In addition the tail plane is a bit raised up fin.
I cant do anything about the angle of the booms but it should be possible to separate the tailplane from the booms and insert a bit of fin section so the tailplane is further away from the exhaust stream.
Well that's the plan.

The tail plane was raised by icutting it from the boom and inserting 6 mm spacers.
Before and after.
 
At the same time the decalage was increased slightly as it was virtually 0:0 and as a result was #flying "on the elevator" with minimal longitudinal stability.
We shall see if the weaterevercalms down a bit. 

In each project there is always something in the drawing that our eyes skip over when we are taking measurements.  Why is it skittish, work back and eventually the AH....
Will be interesting to see how the revised model works.

Really calm and a bit warmer today (1 Oct) so I took the opportunity to fly the Venom twice.
No damage but still not entirely happy with it although the second flight was better having secured the battery so it did not move rearwards on the launch as happened on the first one.
It needed a bit of up elevator but still exhibited some questionable longitudinal stability which suggest to me the decalage needs to be increase a bit further and the CofG moved forward a touch to compensate.
Adding an additonal 2mm tapered insert under the tail plane to decrease its incidence is no problem. 
Most Swiss Venoms were built licence and were given long nose cones 

A bit ugly but the extra length should allow the battery to be moved forward by about 10mm. It just a matter of printing a new nose.
So its press on with the mods as its forecast calm again tomorrow.   

After burning much midnight oil the long nose is fitted and painted to the Bigger Venom.
 
It is not the correct shape for the Swiss Venom but it is the right length.
A true shape Swiss nose will have to wait until the mods and the revised CofG have been shown to work.
It is calm again today so I will let you know shortly..

Two flights today. Rather better behaved so no damage. It flies remarkably fast. Managed both a roll and loop.. 
Still not entrely happy with it characteristics. After a proprely trimmed flight I noted on landing that the elevator was set slightly up. Whilst this could mean slightly nose heavy it could also be inndequate decalge. My monoey is on the decalage so a further "insert" will be made to decrease the tailplane incidence.
Weather looks ideal again tomorrow. 
 

The last little adjustment to the tail incidence seems to have worked. After 2 flights today I made a video of the the thrid.

The QX 50 mm 12 blade fan gives planty of performance, A loop and roll are included.
In the video it was flying at reduced throttle most of the flight which is why I was not too bothered by the 3 minute warning. It should manage atleast 4 minutes of 'modest' flying.