Dreamworks - Ventrix Update
03-02-2021, 04:10 PM
#53
My Feedback: (18)
Mine needed over a half pound of weight in the nose with a K-120 G2. I had read it tended to be tail heavy so Ii always planned to put everything up front. My 3S LiFe battery is in the front hatch. I did use very heavy ProModeler servos in the rear which I am sure contributed to my tail heavy condition. I put the motor as far forward as made sense without risking burning up the aft fuselage. I have not heard of a single one of these coming out nose heavy.
03-02-2021, 06:23 PM
#54
My Feedback: (53)
Mine needed over a half pound of weight in the nose with a K-120 G2. I had read it tended to be tail heavy so Ii always planned to put everything up front. My 3S LiFe battery is in the front hatch. I did use very heavy ProModeler servos in the rear which I am sure contributed to my tail heavy condition. I put the motor as far forward as made sense without risking burning up the aft fuselage. I have not heard of a single one of these coming out nose heavy.
03-10-2021, 07:37 AM
#55
My Feedback: (18)
It should be noted that my C of G is just "theoretical" as I have not flown the plane yet. My Ventrix is set up according to suggestions from various build threads (front edge of the wing tube I think 180 mm from the LE at the root). If I am lucky, the maiden flight will prove that CG to be very nose heavy and I can start removing weight until it's all gone. I doubt I will be able to get rid of all of it but I would be delighted with being able to remove half. 1/4 pound of lead is about all I can tolerate but I am over double that.
03-13-2021, 11:47 AM
#58
Ooooh! sounds heavy. Is it a built up wooden model still?
I saw the Ventrix kits a few years ago at a show in the UK. Gave me some ideas to improve my own design low wing sport model (called Jaylow as it was based on my shoulder-wing JayTee)
My JayLow has wingspan 74", length 76" and dry weight of 6.01 kg (13.2 lb.), so mine is slightly smaller and about half the weight. Mine includes 477g (16.8 oz) of noseweight.
I read that many Ventrix builders get away without noseweight and I wondered how.
I'd dearly like to avoid it on my mark 2.
Maybe I'll stretch the nose and sweep the wings more, like the Ventrix, but I'd really like to keep the weight below 7 kg (15 lb) as models above that generally have a ceiling of 400 feet AGL
I fly my big heavy jet models only at airfields with special permission and ceiling.
I saw the Ventrix kits a few years ago at a show in the UK. Gave me some ideas to improve my own design low wing sport model (called Jaylow as it was based on my shoulder-wing JayTee)
My JayLow has wingspan 74", length 76" and dry weight of 6.01 kg (13.2 lb.), so mine is slightly smaller and about half the weight. Mine includes 477g (16.8 oz) of noseweight.
I read that many Ventrix builders get away without noseweight and I wondered how.
I'd dearly like to avoid it on my mark 2.
Maybe I'll stretch the nose and sweep the wings more, like the Ventrix, but I'd really like to keep the weight below 7 kg (15 lb) as models above that generally have a ceiling of 400 feet AGL
I fly my big heavy jet models only at airfields with special permission and ceiling.
03-15-2021, 03:57 AM
#59
My Feedback: (18)
it's a little on the heavy side but in line with what I would expect for a two meter airplane. My Skymaster / Xtreme Jets Viper Jet is about the same size and weight at 26# dry. They say 24 but once you add a cockpit and such you are pretty much there. Part of the issue with the Ventrix is the extremely heavy Top RC Odyssey landing gear they suggested. Picking up the wing before and after gear installation is almost scary how much weight the gear adds.
I am an old hardcore patter builder and competitor at heart. I would NEVER add an extra unnecessary gram to a pattern plane, but those were fragile and very lightly loaded by comparison. The pattern builder in me is impressed that you can get a jet that size RTF at 13.2 Lbs.
Approximate component weights:
- Turbine installed 2.3 LBS
- Electric landing gear, wheels, brakes, and controller 3.2 Lbs
- Servos Promodeler, excellent servos but very heavy 2.2 oz X 8 = 17.6oz 1.2Lbs
- Various batteries (Life 3200 Mah 9.9v for turbine, 2x2500 Mah 2s lipo for receiver, 3s 2200 for retracts/brakes) about 2Lbs (give or take)
- Receiver, 20 feet of servo extensions, fuel tanks, gyro, UAT, etc, lets say 1Lb but I bet is's more than that.
So before a single sheet of balsa or light ply is glued together, we are already at 9 Pounds 7 ounces (approximately), so the entire airframe, cockpit, covering, pilot, paint, screws, horns, clevices, and everything else would have to be 4 Lbs 9oz to get to 14 pounds.
Again, with over a half pound if lead in the nose I am definitely on the heavy side, but not unreasonable for a jet this size. I have had to rewire my mind from my pattern days and build for a more heavily loaded flying experience. I would never put a pilot, or rubber wheels, or lead in a pattern plane, heck we wouldn't even build in a carbon fiber wing or stab tube that was an extra 1/2 inch longer than absolutely necessary. I build carefully and let the weight come out wherever it does and fly it from there.
So far so good.
I am an old hardcore patter builder and competitor at heart. I would NEVER add an extra unnecessary gram to a pattern plane, but those were fragile and very lightly loaded by comparison. The pattern builder in me is impressed that you can get a jet that size RTF at 13.2 Lbs.
Approximate component weights:
- Turbine installed 2.3 LBS
- Electric landing gear, wheels, brakes, and controller 3.2 Lbs
- Servos Promodeler, excellent servos but very heavy 2.2 oz X 8 = 17.6oz 1.2Lbs
- Various batteries (Life 3200 Mah 9.9v for turbine, 2x2500 Mah 2s lipo for receiver, 3s 2200 for retracts/brakes) about 2Lbs (give or take)
- Receiver, 20 feet of servo extensions, fuel tanks, gyro, UAT, etc, lets say 1Lb but I bet is's more than that.
So before a single sheet of balsa or light ply is glued together, we are already at 9 Pounds 7 ounces (approximately), so the entire airframe, cockpit, covering, pilot, paint, screws, horns, clevices, and everything else would have to be 4 Lbs 9oz to get to 14 pounds.
Again, with over a half pound if lead in the nose I am definitely on the heavy side, but not unreasonable for a jet this size. I have had to rewire my mind from my pattern days and build for a more heavily loaded flying experience. I would never put a pilot, or rubber wheels, or lead in a pattern plane, heck we wouldn't even build in a carbon fiber wing or stab tube that was an extra 1/2 inch longer than absolutely necessary. I build carefully and let the weight come out wherever it does and fly it from there.
So far so good.
06-14-2021, 04:51 AM
#61
06-14-2021, 04:31 PM
#63
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MikePS (06-29-2021)
06-29-2021, 11:44 AM
#68
07-05-2021, 03:39 AM
#69
My stopper came loose snd leaked diesel inside my fuse. I cleaner her up best I could (and promptly bought a new good tank) but the wood is saturated. I used powder to sop up the worst snd have a fan on her now. Any thing else I can do to help dry it out?
Last edited by Fili; 07-05-2021 at 03:42 AM.
07-05-2021, 04:23 AM
#70
My Feedback: (53)
First you should ditch that tank and get something with vent and feed on different fitting….I think Dreamworks sell one for this jet.
Using carpet cleaner K2R should lift the fuel from the wood, I haven’t had the need to use it yet, I also do a couple of thin epoxy coat on the wood in case of leaks…using Finishing epoxy with a little of 99% alcohol to make it event] thinner….
Using carpet cleaner K2R should lift the fuel from the wood, I haven’t had the need to use it yet, I also do a couple of thin epoxy coat on the wood in case of leaks…using Finishing epoxy with a little of 99% alcohol to make it event] thinner….
07-05-2021, 06:13 AM
#72
First you should ditch that tank and get something with vent and feed on different fitting….I think Dreamworks sell one for this jet.
Using carpet cleaner K2R should lift the fuel from the wood, I haven’t had the need to use it yet, I also do a couple of thin epoxy coat on the wood in case of leaks…using Finishing epoxy with a little of 99% alcohol to make it event] thinner….
Using carpet cleaner K2R should lift the fuel from the wood, I haven’t had the need to use it yet, I also do a couple of thin epoxy coat on the wood in case of leaks…using Finishing epoxy with a little of 99% alcohol to make it event] thinner….
Thanks for the tips Guys! Much appreciated!
07-08-2021, 03:16 AM
#75