CMPro Ventus 2HX ARF - Page 3

Stevepilot · Jun 08, 2008, 02:52 AM

For what it's worth,I'd seriously NOT use 56's all round. I wouldn't use em period. Limited experience has shown me that from now on I won't bother with anything but MG's for ailerons and certainly the tow release, certainly if the performance on this is like the Discus. The tow release needs a beefy servo or it won't work and you'll end up with a stripped servo and a tug, desperately (or the pilot at least!)trying to off load an un offloadable glider. I'd use 81 or 82 MG's in the wings a small MG in the fin and a beefy standard for the rudder. The retract is a joke and I would seal that shut-it has 'ripped off first landing' written all over it. I'll possibly get one of these but can't myself using the tow or the retract. Sorry to sound negative guys.

jason H · Jun 08, 2008, 03:27 AM

Hey Steve,

Yer I think you maybe right about using a MG on the tow release. I think I may use 81 MG's on the release, retract and airbrake. With regards to the 56's, I've been using them in my Discus for a year now with no problem. I think that if they are strong enough for the Trex 450 flying full 3D then they'll be fine in the Ventus. Also I would like to add that my Ventus may see nothing but thermalie type flying from a tar strip.

jason H · Jun 08, 2008, 05:47 AM

Tips have now been glued on with epoxy and microballons.

excelpoint · Jun 08, 2008, 05:52 AM

Lookin good Jas. Why the use of micro balloons?

Big Nuts 181 · Jun 08, 2008, 06:08 AM

Quote:

Originally Posted by jason H

Next up was the spoilers. The manual calls for the covering to be cut back and sealed over into the cavity before glueing in the spoilers with epoxy. I didn't do that

, I really don't like seeing the red of the airbrake while they are closed so I cut the covering back, slide the spoiler into the cavity and CA'ed it in. Then I sealed the covering back over the spoiler housing. The top of the spoiler was then sealed with Profilm to match the top of the wing. Dosen't look to bad, just need to work out some of the air bubbles.

Hi there Jason looking good tell me is there enough depth to put the airbrakes in the scale location behind the spar?

Rossco.

jason H · Jun 08, 2008, 06:35 AM

Excell, by adding microballons you cut down on the weight.

Ross, yer I recon you could get them behind the spar. Having the flat airbrake in the front 1/3 of the airfoil sorta looks abit dicky but for under $200.....

excelpoint · Jun 08, 2008, 06:43 AM

Quote:

Originally Posted by jason H

Excell, by adding microballons you cut down on the weight.

Fair enough. Who says you cant learn something new every day

jason H · Jun 14, 2008, 08:16 PM

Well after a week away from the Ventus repairing other pilots planes it's time to do abit more to my new bird.....

I mounted the retract last night with no major problem. This is a straight forward task and the instruction show it very clearly. Once you have the wheels in the next task is to epoxy in the retract door, once again another easy step. Blue masking tape marked out the cut-out of the doors and where the hinges where so as I didn't glue them shut. 5min epoxy was mixed up with white microballoons to make a slurry. The white microballoons worked out well as they are the same colour as the fuze and they acted as a filler.

jason H · Jun 14, 2008, 08:32 PM

Ok so that all seemed to go well and to this point everything has been a breeze but......

It's time to see if the retract and gear doors work together and to do this you need to add a link between the retract mech and the gear doors themselves. No I know that this sound simple but trust me when I say "Your gunna ripe your hair out". The instructions state the the lenght of the link MUST be 28mm, not so. My link is down to 14mm to get the doors to close tight when the wheel is retracted. The other problem was getting the damm link in and out to adjust the lenght, this was the hardest part to do and it took me near on 2hrs to complete. But it was worth it as the retract and gear door work sweet. I also took Stevepilots advice and added a HS 81MG for the retract, thatnx Steve.

Stevepilot · Jun 15, 2008, 07:30 AM

Agree with the clevis and push rod replacement Jason-It isn't really surprising how models such as this are so cheap, you end up spending a small fortune on making the job usable all for the sake of a few quid at their end. I take it the instructions do make sure the builder knows to check the cg with the retract retracted?

Mr.Buzzy · Jun 19, 2008, 01:39 AM

Hi all,
may be a silly question but would it not pay to use a retract servo for the retract? Isn't a standard servo going to stay powered and possibly loaded while enjoying long relaxing thermal sessions?

Stevepilot · Jun 19, 2008, 04:30 PM

Without looking at it Mr Buzzy, I suspect the design on the retract goes over centre and the servo returns to centre after each opposite direction actuations... But yes, a retract servo would be better on a couple of points, stronger and as you've stated load off at each end of throw.

But frankly I wouldn't waste any servo on this retract,unless it is guarenteed to land on a green next to the nineteenth hole

.

Mr.Buzzy · Jun 19, 2008, 10:47 PM

Thanks Steve,
I tend to agree with your opinion of the retractable wheel. I think I may build mine with the supplied spoilers and perhaps install the undercart with a small retract servo and have the whole plastic fantastic assembly easily removable to avoid further damage in my frustrated state of rage when it goes kerploing!
Cheers

Straight Up · Jun 23, 2008, 07:53 AM

Looking damn fine, Jason! Nice work with the retract doors. I look forward to hearing how it all works out - especially the retract's ability to stand-up to landings. I'm not writing it off just yet.

Any idea on the completion date? Not intending to sound like I'm pushing you. I only just found this thread, and I'm already keen-as to read a flight report.

To all-and-sundry, how well do these birds thermal? I know we don't have a flight report yet on THIS bird, but the Discus has been around for a while, as has the DG1000. They're all very similar - high aspect ratio large-span "slippers", with wing-loadings around 14oz/sq.ft. I have no doubt they can achieve high speeds, but their wingloadings are a bit higher than I'd prefer to see for a pure thermal soarer (my rule of thumb is 10 max). However, I also believe that long, hi-aspect wings are more efficient than shorter low-aspect wings, so wing-loadings are not a 100% indicator. I ask because I'd really like to get a scale soarer like this for pure thermal soaring, but I don't want to end up with a lead-sled.

I currently fly an electric soarer with a loading of 9oz/sq.ft and 6ft wingspan (sorry for imperials - I'm old-school, but also an Aussie by origin!) and I'm very happy with its thermalling performance. In the case of the Discus / Ventus / DG I'm not expecting open-class thermal soarer performance, but I also don't want to be launching every 2 minutes. Anyone care to comment on what I can REALISTICALLY expect? I fully understand that long-duration thermal soaring is also *highly* dependent on pilot skill - please don't lecture me on this. I want to know how the bird flies - can it sink slowly, does it turn tight but flat, does it react to lift, and how long does it last from a dead-air launch (and how long is a piece of string?).

Thanks for any feedback,
Straight Up

Stevepilot · Jun 23, 2008, 01:08 PM

Hi Straightup, as you're probably aware there are entire threads running into many hundreds of pages on the Discus and the DG1000. I had the Discus, and only sloped it, but found although it would climb like a homesick angel it needed quite a high wind to stay there, thermalling being okay as long as the speed was kept up. It wasn't built heavy either so I took it as the nature of the beast.

Jun 08, 2008, 05:47 AM	#33
jason H Magic Blue Smoke costs to much Join Date: Dec 2004 Location: Melbourne, AUSTRALIA Posts: 2,537	Tips have now been glued on with epoxy and microballons. Attached Thumbnails 39.1 KB · Views: 612

Jun 14, 2008, 08:16 PM	#38
jason H Magic Blue Smoke costs to much Join Date: Dec 2004 Location: Melbourne, AUSTRALIA Posts: 2,537	Retract landing gear and doors. Well after a week away from the Ventus repairing other pilots planes it's time to do abit more to my new bird..... I mounted the retract last night with no major problem. This is a straight forward task and the instruction show it very clearly. Once you have the wheels in the next task is to epoxy in the retract door, once again another easy step. Blue masking tape marked out the cut-out of the doors and where the hinges where so as I didn't glue them shut. 5min epoxy was mixed up with white microballoons to make a slurry. The white microballoons worked out well as they are the same colour as the fuze and they acted as a filler. Attached Thumbnails retract gear locked into fuze by glueing in front ply plate. 58.7 KB · Views: 829 fuze preped for glueing in of gear doors, note hinge cut-outs. 63.7 KB · Views: 862 close-up of gear door, vaseline was rubbed into the hinges to protect them from being glued shut. 85.2 KB · Views: 661 Gear doors glued in with epoxy and microballoons. 57.6 KB · Views: 693 Finished product, looks neat and works well. 44.0 KB · Views: 780

Jun 14, 2008, 08:32 PM	#39
jason H Magic Blue Smoke costs to much Join Date: Dec 2004 Location: Melbourne, AUSTRALIA Posts: 2,537	Ok so that all seemed to go well and to this point everything has been a breeze but...... It's time to see if the retract and gear doors work together and to do this you need to add a link between the retract mech and the gear doors themselves. No I know that this sound simple but trust me when I say "Your gunna ripe your hair out". The instructions state the the lenght of the link MUST be 28mm, not so. My link is down to 14mm to get the doors to close tight when the wheel is retracted. The other problem was getting the damm link in and out to adjust the lenght, this was the hardest part to do and it took me near on 2hrs to complete. But it was worth it as the retract and gear door work sweet. I also took Stevepilots advice and added a HS 81MG for the retract, thatnx Steve. Attached Thumbnails Note the link infront of the retract, this was a bloody pain in the bum to get right. 58.7 KB · Views: 731 Retract servo added and tested. Runs well and looks great. Also note that I replaced the crap links and rods that are supplied in the kit for Dubro 4-40 rod and metal clevis's, much much stronger. 74.4 KB · Views: 1165

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Jun 08, 2008, 02:52 AM	#31
Stevepilot aka : SteveBB.. Join Date: May 2007 Location: South Yorkshire,England Posts: 402	For what it's worth,I'd seriously NOT use 56's all round. I wouldn't use em period. Limited experience has shown me that from now on I won't bother with anything but MG's for ailerons and certainly the tow release, certainly if the performance on this is like the Discus. The tow release needs a beefy servo or it won't work and you'll end up with a stripped servo and a tug, desperately (or the pilot at least!)trying to off load an un offloadable glider. I'd use 81 or 82 MG's in the wings a small MG in the fin and a beefy standard for the rudder. The retract is a joke and I would seal that shut-it has 'ripped off first landing' written all over it. I'll possibly get one of these but can't myself using the tow or the retract. Sorry to sound negative guys.

Jun 08, 2008, 03:27 AM	#32
jason H Magic Blue Smoke costs to much Join Date: Dec 2004 Location: Melbourne, AUSTRALIA Posts: 2,537	Hey Steve, Yer I think you maybe right about using a MG on the tow release. I think I may use 81 MG's on the release, retract and airbrake. With regards to the 56's, I've been using them in my Discus for a year now with no problem. I think that if they are strong enough for the Trex 450 flying full 3D then they'll be fine in the Ventus. Also I would like to add that my Ventus may see nothing but thermalie type flying from a tar strip.

Jun 08, 2008, 05:52 AM	#34
excelpoint Registered User Join Date: May 2004 Location: Melbourne Posts: 640	Lookin good Jas. Why the use of micro balloons?

Jun 08, 2008, 06:35 AM	#36
jason H Magic Blue Smoke costs to much Join Date: Dec 2004 Location: Melbourne, AUSTRALIA Posts: 2,537	Excell, by adding microballons you cut down on the weight. Ross, yer I recon you could get them behind the spar. Having the flat airbrake in the front 1/3 of the airfoil sorta looks abit dicky but for under $200.....

Jun 15, 2008, 07:30 AM	#40
Stevepilot aka : SteveBB.. Join Date: May 2007 Location: South Yorkshire,England Posts: 402	Agree with the clevis and push rod replacement Jason-It isn't really surprising how models such as this are so cheap, you end up spending a small fortune on making the job usable all for the sake of a few quid at their end. I take it the instructions do make sure the builder knows to check the cg with the retract retracted?

Jun 19, 2008, 01:39 AM	#41
Mr.Buzzy Registered User Join Date: Dec 2005 Posts: 127	Hi all, may be a silly question but would it not pay to use a retract servo for the retract? Isn't a standard servo going to stay powered and possibly loaded while enjoying long relaxing thermal sessions?

Jun 19, 2008, 04:30 PM	#42
Stevepilot aka : SteveBB.. Join Date: May 2007 Location: South Yorkshire,England Posts: 402	Without looking at it Mr Buzzy, I suspect the design on the retract goes over centre and the servo returns to centre after each opposite direction actuations... But yes, a retract servo would be better on a couple of points, stronger and as you've stated load off at each end of throw. But frankly I wouldn't waste any servo on this retract,unless it is guarenteed to land on a green next to the nineteenth hole .

Jun 19, 2008, 10:47 PM	#43
Mr.Buzzy Registered User Join Date: Dec 2005 Posts: 127	Thanks Steve, I tend to agree with your opinion of the retractable wheel. I think I may build mine with the supplied spoilers and perhaps install the undercart with a small retract servo and have the whole plastic fantastic assembly easily removable to avoid further damage in my frustrated state of rage when it goes kerploing! Cheers

Jun 23, 2008, 07:53 AM	#44
Straight Up Vertical Unlimited Join Date: Mar 2007 Location: Mississauga, Toronto, Canada Posts: 227	Looking damn fine, Jason! Nice work with the retract doors. I look forward to hearing how it all works out - especially the retract's ability to stand-up to landings. I'm not writing it off just yet. Any idea on the completion date? Not intending to sound like I'm pushing you. I only just found this thread, and I'm already keen-as to read a flight report. To all-and-sundry, how well do these birds thermal? I know we don't have a flight report yet on THIS bird, but the Discus has been around for a while, as has the DG1000. They're all very similar - high aspect ratio large-span "slippers", with wing-loadings around 14oz/sq.ft. I have no doubt they can achieve high speeds, but their wingloadings are a bit higher than I'd prefer to see for a pure thermal soarer (my rule of thumb is 10 max). However, I also believe that long, hi-aspect wings are more efficient than shorter low-aspect wings, so wing-loadings are not a 100% indicator. I ask because I'd really like to get a scale soarer like this for pure thermal soaring, but I don't want to end up with a lead-sled. I currently fly an electric soarer with a loading of 9oz/sq.ft and 6ft wingspan (sorry for imperials - I'm old-school, but also an Aussie by origin!) and I'm very happy with its thermalling performance. In the case of the Discus / Ventus / DG I'm not expecting open-class thermal soarer performance, but I also don't want to be launching every 2 minutes. Anyone care to comment on what I can REALISTICALLY expect? I fully understand that long-duration thermal soaring is also highly dependent on pilot skill - please don't lecture me on this. I want to know how the bird flies - can it sink slowly, does it turn tight but flat, does it react to lift, and how long does it last from a dead-air launch (and how long is a piece of string?). Thanks for any feedback, Straight Up

Jun 23, 2008, 01:08 PM	#45
Stevepilot aka : SteveBB.. Join Date: May 2007 Location: South Yorkshire,England Posts: 402	Hi Straightup, as you're probably aware there are entire threads running into many hundreds of pages on the Discus and the DG1000. I had the Discus, and only sloped it, but found although it would climb like a homesick angel it needed quite a high wind to stay there, thermalling being okay as long as the speed was kept up. It wasn't built heavy either so I took it as the nature of the beast.