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Old Feb 13, 2012, 10:26 PM
Feeling the THRALL
Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
819 Posts
Ventus Build Underway

I have been building my Ventus for the last three days. The wings are done. Fuselage is joined with motor and electronics installed. Ready for finishing. Will add the horizontal stab as a final step. I have carefully mined the ideas on this thread and taken pictures along the way. Will make a detailed build post soon.

One question. There are two carbon fiber pieces apparently included to mount the wing. One is a relative short carbon tube which fits neatly in the aft mounting tube. The other is a square piece of even shorter dimension and clearly the wrong diameter (too small) to act as a joining piece. It seems logical to me to put a fairly long CF tube in the front mounting tube, as this tube traverses almost the full wingspan. Any experience on this issue?


Cheers from Colorado,

Jackson Stone
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Old Feb 14, 2012, 10:43 AM
Drifting off the reservation..
JumpySticks's Avatar
USA, LA, Broussard
Joined Jan 2011
2,296 Posts
I only use the CF tube in the rear (round) hole. It slides inside the aluminum tubes which are then screwed into the fuse with grub screws. The grub screws grab the aluminum tube.

There was nothing in the RTF kit to insert into the front, square tubes.

Caution...this plane is very CG sensitive. I haven't yet found the proper CG but haven't had many flights since the extensive rebuild.
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Old Feb 14, 2012, 09:43 PM
Feeling the THRALL
Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
819 Posts
Wing Tubes

Quote:
Originally Posted by JumpySticks View Post
I only use the CF tube in the rear (round) hole. It slides inside the aluminum tubes which are then screwed into the fuse with grub screws. The grub screws grab the aluminum tube.

There was nothing in the RTF kit to insert into the front, square tubes.

Caution...this plane is very CG sensitive. I haven't yet found the proper CG but haven't had many flights since the extensive rebuild.
Hi Jumpy,

Thanks for the feedback. I found that the 6mm carbon fiber tube fits nicely in the front, square tube. Note that the front tube has a circular inner diameter. So, I ordered a 1 meter 6mm cf tube to fit in the front tube. This will give me a slightly stouter wing. Will use the supplied, 6mm cf tube in the aft, aluminum tubes as it is clearly designed to fit there.

I hear you loud and clear about CoG! With such a thin wing chord it is likely to be hyper sensitive. I am putting more weight in the tail section as I build it. Hope to be close to optimal CG and use weights or battery size/position to achieve optimal CG. Is there a consensus opinion that you have seen on the CG position?

Cheers,

Jackson
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Old Feb 14, 2012, 10:23 PM
Drifting off the reservation..
JumpySticks's Avatar
USA, LA, Broussard
Joined Jan 2011
2,296 Posts
Quote:
Originally Posted by Jackson Stone View Post
Hi Jumpy,

Thanks for the feedback. I found that the 6mm carbon fiber tube fits nicely in the front, square tube. Note that the front tube has a circular inner diameter. So, I ordered a 1 meter 6mm cf tube to fit in the front tube. This will give me a slightly stouter wing. Will use the supplied, 6mm cf tube in the aft, aluminum tubes as it is clearly designed to fit there.

I hear you loud and clear about CoG! With such a thin wing chord it is likely to be hyper sensitive. I am putting more weight in the tail section as I build it. Hope to be close to optimal CG and use weights or battery size/position to achieve optimal CG. Is there a consensus opinion that you have seen on the CG position?

Cheers,

Jackson
I think the wings were redesigned, and are stiffer than the original release. I don't see the need for an additional tube in mine.

For CG I've seen posts say 45mm, and others say at the servo cables. I certainly have not found the proper cg yet for mine after only a few flights. I thought it was nose heavy and so mounted a keycam atop the stabilizer. Not sure if it put too much weight back, or if the cam is turbulating the stab, but the last flights were very unstable (porpoising badly). So bad I put it aside and flew my Radian Pro. Here is the very pitchy video up until the new camera cut off prematurely.
HK Ventus Re-Maiden (3 min 40 sec)
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Old Feb 14, 2012, 10:59 PM
Feeling the THRALL
Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
819 Posts
Don,

I suspect you are tail heavy. Porpoising is often caused by an aft-CoG position.

My experiment with epoxying the fuselage tonight was much less than satisfactory. I was hoping for a very smooth finish, like the Polyacrylic, but the epoxy was much more viscous and has created an uneven finish. Tried to brush it smooth, but the final result is disappointing. It is curing right now. I will take another look in the morning and decide what to do next. I note that the finish on your Ventus from the video is excellent. What did you do, if anything, to achieve it?

Regards,

Jackson
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Old Feb 15, 2012, 09:49 AM
Drifting off the reservation..
JumpySticks's Avatar
USA, LA, Broussard
Joined Jan 2011
2,296 Posts
Quote:
Originally Posted by Jackson Stone View Post
Don,

I suspect you are tail heavy. Porpoising is often caused by an aft-CoG position.

My experiment with epoxying the fuselage tonight was much less than satisfactory. I was hoping for a very smooth finish, like the Polyacrylic, but the epoxy was much more viscous and has created an uneven finish. Tried to brush it smooth, but the final result is disappointing. It is curing right now. I will take another look in the morning and decide what to do next. I note that the finish on your Ventus from the video is excellent. What did you do, if anything, to achieve it?

Regards,

Jackson
Nothing. It came stock very smooth. Much slicker than my Radian Pro.
I expect it will get dinged up eventually though.
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Old Feb 15, 2012, 06:54 PM
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Galand's Avatar
Long Island, NY
Joined May 2010
1,601 Posts
On the Minimoa thread we ended up talking about the Ventus and instead of hijacking that thread, I am posting some pic's here.
I have not followed this thread recently but I picked up a lot of good advice from it.
Finished my Ventus a while ago and it flies beautifully.
Ventus Hobbyking 2.3m EPO Motorized Glider Maiden (5 min 39 sec)

I did not make any really original mods except that I decided not to mount the landing wheel to save weight and to be able to use the opening to slide the battery into the belly, allowing me to move the CG at will. It also makes more room in the cockpit.
I put in a Turnigy 2836 1000kV with a 2S 2650mAh battery. It does the job and lasts forever it seems.
Oh, also I taped the two fuselage halves together with 3M transparent "Heavy Duty" packing tape. Luckily I did so, because my tail rod was not sitting completely straight. So it was easy to take the fuse apart again and correct it.
A bonus with the picture of the real one!
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Old Feb 18, 2012, 12:40 AM
Feeling the THRALL
Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
819 Posts
Galand's Ventus

Galand,

Very nice job on the build and the flying of your Ventus! I had previously watched your video on YouTube.

I am nearing completion on my Ventus, hope to finish the build tomorrow and maiden on Sunday. I have taken photos along the way so I will post a build log with some of the important steps I took. I have built mine to accommodate a larger motor and power it with an 1800 mAh 3S battery. Have finished all the surfaces with polyacrylic which adds some weight and reduces drag. Should be more of a warm liner than yours because of these mods.

Regards,

Jackson
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Old Feb 18, 2012, 04:51 AM
Good Better Best quest.
olmod's Avatar
Australia, VIC, Cranbourne East
Joined Apr 2004
10,519 Posts
Beware high speed she will flutter like a butterfly .
very good on light air days for thermalling use the downtrim setting to lose altitude rather than diving steeply.
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Old Feb 18, 2012, 02:21 PM
Feeling the THRALL
Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
819 Posts
Flutter

Quote:
Originally Posted by olmod View Post
Beware high speed she will flutter like a butterfly .
very good on light air days for thermalling use the downtrim setting to lose altitude rather than diving steeply.
Hi Olmod,

Thanks for the warning on high speed flutter.

I am in the middle of a good flying day. Hope to work on the Ventus later today and maiden tomorrow. I am excited to see her in the air. Such a pretty plane! I have a few odds and ends to complete, then I need to balance for proper CG.

If all goes well I will have a maiden report tomorrow.

Jackson
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Old Feb 18, 2012, 04:29 PM
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Galand's Avatar
Long Island, NY
Joined May 2010
1,601 Posts
[QUOTE=olmod;20781936]Beware high speed she will flutter like a butterfly .


What happened?
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Old Feb 18, 2012, 07:37 PM
Drifting off the reservation..
JumpySticks's Avatar
USA, LA, Broussard
Joined Jan 2011
2,296 Posts
Quote:
Originally Posted by olmod View Post
Beware high speed she will flutter like a butterfly .
very good on light air days for thermalling use the downtrim setting to lose altitude rather than diving steeply.
The wings were veinforced in later releases. Mine has two sets of CF strips, making the wings heavier but they seem very stiff to me.
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Old Feb 19, 2012, 04:40 PM
Good Better Best quest.
olmod's Avatar
Australia, VIC, Cranbourne East
Joined Apr 2004
10,519 Posts
Mine was one of the first and the wing tubes werent even long enough to lock to the centre , good to hear they improved the wings tho'
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Old Feb 19, 2012, 05:57 PM
Drifting off the reservation..
JumpySticks's Avatar
USA, LA, Broussard
Joined Jan 2011
2,296 Posts
I went out and flew the Ventus some today. Still fighting with the cg, but getting closer.

This plane is heavy for the wing area....not a thermal sailplane. I think I'll be looking at it more than flying it.
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Old Feb 20, 2012, 12:32 AM
Feeling the THRALL
Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
819 Posts
Ready to Maiden

The Ventus is ready to maiden. I set up the plane tonight and finalized all the control surface settings, retract operation, and set the ESC brake on. I tested the motor/prop combination on the wattmeter and was pulling 200 watts at 19 amps. This is using a 10x8 folding prop and an 1800 mAh 3S battery. I also finalized the canopy latch mechanism using some strong magnets to hold the canopy in the back and some metal pins into a plastic mounting plate in the front.

The CoG measures at 43mm back from the leading edge. I am running both a 1 meter 6mm carbon fiber rod as a doubler in the front (full wingspan) spar, and the provided 30 cm 6mm carbon fiber rod in the main aluminum spar. The wings have some flex but not the major flex reported by users of V 1.0 of the plane.

I will post a build log and some photos tomorrow.

Wish me a successful maiden.

Regards,

Jackson
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