Turbine Venom

[Jhnybgd]

Hey guys,
I am looking to try a turbine soon.

Looking at the available "donor" planes I am thinking about using the 90mm Venom.

Has this been done already?

It looks like this would be a good way to not need a thrust tube with the centralized exhaust.

I am concerned of the heat on the horizontal stabilizer,which I guess could be protected by aluminum tape or maybe replaced by balsa/fiberglass?

What you guys think?

[Alpha]

Hey there Jhnybgd,
As much as I love it in 6s Inrunner form, I wouldn't recommend the Freewing 90mm Venom for a turbine conversion for the following two reasons:

1) The Venom's elevator needs airflow to be effective. Incidentally, this is why some have reported bouncy landings, because typically the elevator loses effectiveness which can contribute to its inability to sustain flare and then pin the nose to the ground. I don't think aluminum tape alone will provide a sufficient heat shield. Keep in mind that the elevator servo is positioned right there in the airflow, as well. If you did fabricate a new horizontal stabilizer our of a proper material, you'd also need to relocate the servo, and also look at reinforcing the booms... their current design isn't intended for the rigors of turbine power and can develop a noticeable flex. Even after addressing all that, you'd still need to surmount the second challenge...

2) The Venom doesn't have much space on its CG for a fuel tank of meaningful size. If you're handy with removing foam and fabricating a conformal fuel tank, you *might* be able to get enough capacity. But the consumption on a P20 and even a Kolibri would be a tough target in the Venom. I can fly my 6s inrunner for 5-7 minutes already, with a ten foot stop-to-rotation followed by a vertical climbout to treetop level before leveling out... without the hassles of turbine maintenance.

2.5) If you're in the States and flying at an AMA field with a waiver, you would need to install brakes, and the Venom's wells would likely need to be widened. Be careful because the foam on the top of the wing opposite the well is fairly thin.

Overall, the static efflux from a turbine wouldn't be a bad thing on a model like the Venom --it would probably help the model land more consistently, if anything. Like the BVM Kingcats and Feibao Veloxes of the world, this planform is a good one, IF you can sort out the fuel challenges specific to the Venom. Those aforementioned "fantasy" jets locate the turbine outside of the blended fuselage, and their horizontal stabs are purposely positioned higher out of the airflow.

If you do decide to give it a shot, let us know how it goes.

[Jhnybgd]

Thanks Alpha,

thats what I needed.

Still am going to get a Venom though it looks like it flies fantastic:Cool:

[Aussie1]

Hey guys,
I am looking to try a turbine soon.

Looking at the available "donor" planes I am thinking about using the 90mm Venom.

Has this been done already?

It looks like this would be a good way to not need a thrust tube with the centralized exhaust.

I am concerned of the heat on the horizontal stabilizer,which I guess could be protected by aluminum tape or maybe replaced by balsa/fiberglass?

What you guys think?

I have one with a P20 in it and have clocked up about 10 flights. It came in at 3.5 kgs with 600 mils of fuel, and I set my timer at 7 mins and it lands with around 2 mins of fuel remaining. Alpha makes some valid points, but with care, can be overcome. The fuel tank is just a diced fruit rectangular plastic bottle and I made a aluminium cover for the elevator servo and use two layers of Speed Tape over the stab and have had no problems with heat. Some guys use a bit of gal downpipe with some legs positioned behind the turbine during start to protect rear stabs. It is a draggy air-frame and won't fly much faster than the EDF version, just gets lighter as the flight progresses! Plenty of room for a tank, just keep removing foam! The short nose requires 150 grams of lead up front, but still very light and the Swiss colour scheme is great for seeing it in the air.I have two K30 turbines and these are a much nicer, user friendly engine compared to the P20, but are 80 grams heavier than the P20. Overall, really happy with the Venum, so go for it! Sorry for doubling up on some pics, but I can't seem to be able to remove them, using the Edit function.

[Alpha]

Thanks for posting with your insight and photos, Aussie1! Did you reinforce the boom joints? Do you have brakes? I like your hatch, it's very user friendly.

I agree, P20 is the way to go for a model this size. K30 would be nice in some of our larger models, but I can't think of one now where an install would be straightforward. Maybe the L-39 with a new hatch cut, or the Avanti.

The P20 in the Stinger 90 flew alright, but not amazingly. It gained more in duration than it did in speed.

[Aussie1]

Thanks for posting with your insight and photos, Aussie1! Did you reinforce the boom joints? Do you have brakes? I like your hatch, it's very user friendly.

I agree, P20 is the way to go for a model this size. K30 would be nice in some of our larger models, but I can't think of one now where an install would be straightforward. Maybe the L-39 with a new hatch cut, or the Avanti.

The P20 in the Stinger 90 flew alright, but not amazingly. It gained more in duration than it did in speed.

Alpha, no problems mate! I glassed around the boom to fuselage join, but possibly not needed, just made me feel better! I now have many flights on my small jets using the K30, and I would estimate its power to be about the same as a 12S setup. There are plenty of videos on the net of the K30 flying jets of over 5 kgs and my latest creation is a Freewing F14 Tomcat with K30, so can't wait to get that going! There are several L-39's flying over here with the K30 and they fly like a big trainer jet. Brakes are no longer required on turbine jets here down under, and are not really required for small light foam jets, especially off grass.To satisfy USA rules, a single nose wheel brake will work on a small jet quite well. The rear hatch is very easy and I just use two hinges on one side and a simple screw lock on the opposite side.

https://sigmfg.com/products/kavan-electro-magentic-brake

[Jhnybgd]

Alpha, no problems mate! I glassed around the boom to fuselage join, but possibly not needed, just made me feel better! I now have many flights on my small jets using the K30, and I would estimate its power to be about the same as a 12S setup. There are plenty of videos on the net of the K30 flying jets of over 5 kgs and my latest creation is a Freewing F14 Tomcat with K30, so can't wait to get that going! There are several L-39's flying over here with the K30 and they fly like a big trainer jet. Brakes are no longer required on turbine jets here down under, and are not really required for small light foam jets, especially off grass.To satisfy USA rules, a single nose wheel brake will work on a small jet quite well. The rear hatch is very easy and I just use two hinges on one side and a simple screw lock on the opposite side.
https://sigmfg.com/products/kavan-el...magentic-brake

Thanks Aussie,
Love the Venom!

Still just pondering at the moment.

I started this thread with all intent of getting the venom flying it stock and then possibly going with a P20,that was before Motion announced the F18.

So still deciding what i am going to do?:Silly:

[Aussie1]

Thanks Aussie,
Love the Venom!

Still just pondering at the moment.

I started this thread with all intent of getting the venom flying it stock and then possibly going with a P20,that was before Motion announced the F18.

So still deciding what i am going to do?:Silly:

The Venom is a great little turbine jet, but lead is required to get the CG right, and I hate adding lead! There is not a lot of room up front to put larger batteries, so now if I had the choice of the F18, I would choose it because it has a long fuselage with loads of room for a fuel tank and turbine components. Also, if you check that video link that I added with a P20 in the Banana Hobby F18, it lends itself to a rear mounted or under slung turbine mount.