Another Venturi build

[Big_Tone]

The Venturi arrived. It looks great, but only having built Bixlers before it looks a whole lot more involved. I seemed to get two motor mounts (ordered one) and four clevices.

Having decided on 3s, I need to now decide on LiPos. Still keen to use existing batts. Options are either 2200 mah turnigys or 4000 mah compact zippys.

Layout wise, it seems fairly important to decide on what batts I'll be using. I made the table below:

Batt                                        Tot weight   Tot mah      mah/g
3x Turnigy 3s 2200mah             561      6600      11.76
2x Zippy compact 3s 4000mah   572      8000      13.98
1x Zippy compact 3s 4000mah   286      4000      13.98
2x Turnigy 3s 3300mah              556      6600      11.87
1x Gen Ace 3s 5000                   413      5000      12.10
         
Last two lines are batts I don't have but are for comparison. The Turnigy 2x 3300 mah seems like a classic setup used a lot. Delta tango suggested Gen Ace 5000 3s, for possible interchange with 4s later. It seems like using 1x Zippy 4000mah would make for a very light build which might fly slower and glide more for learning and close range hooning about. 2 Zippys would give some serious mah, and based upon other people's set-ups would still be flyable as it's only a few more grams than 2x turnigy 3300mahs. The Zippys seem to give more mah per gram too, although they might make up for it in other ways.

I'm going to use the Zippys. Will try and build a batt box that can take either one or two. That way if i'm flying close range then I can have shorter flights, change the batt more often and not carry the weight of the second one. If I'm flying long then I can use two. That means the battery bay will have to be in the centre for balance as I might fly with only one batt and will have to be able to secure one batt centrally or two next to each other.

Also got a little overexcited whist on HobbyKing and ordered the orange openlrs tx/rx. Will be flashing to 459 mhz and building an IB Crazy turnstile antenna on the wing.

Found an iPhone app called Electric RC by jetstripes. It seems way more realistic than the other ones I have for my phone and the 69p version has a flying wing. Haven't flown a real wing yet, but it seems fairly similar in flight characteristics to the one on RealFlight.

[Madmax]

cool, be interested to see how it flies as interested in getting one of these or a team black sheep wing after my quad copters  ;D

[Brucey]

I had 2x 3s 3300 in mine, and a fair about of lead.
Yes it is a more involved build and a bixler. Just take your time and lay everything out to get that CofG as close as possible.

[skyscraper]

Re the Orange OpenLRS . I bought one, but on 459 MHz it seemed to have much less range than my FrSky 2.4 GHz system. ( I would like to have another go sometime but currently its just lying in a box and Ive gone back to FrSky) Maybe  I had a bad one, but just make sure you can replace it with another RC system if necessary if it doesnt work well..

regards
Andy

[Big_Tone]

Bleh, I currently run frsky 2.4 and was hoping it would be an upgrade. Thanks for the heads up. Will build it accessible.

[Big_Tone]

Here's my attempt at a turnstile antenna. Built on a piece of card through a hole as will be mounting on bottom of wing with rx on top. Not sure how long to cut the wires for 459. All instructions I found so far  are for 433.

[Big_Tone]

For the record, if anyone is attemting the same I have calculated the following for 459 mhz turnstile lengths:

Long arms: 161.7 mm (6.37 inches)
Short arms: 140.2mm (5.52 inches)

IBCrazy gave the following formula to adapt from 433 mhz: size = Frequency in design/your frequency * size in design

It's just inversely proportional.

[iPeel]

I'd be interested to know how you get on. I've tried a turnstile on 459mhz and got some pretty bad nulls when the plane was pointing in certain directions. In the end I went back to a dipole.


Neil.

[Big_Tone]

I'm starting to question how much better hk orange openlrs at 100mw will actually be over my frsky 2.4. Will give it a bash.

[rob.thomson]

I have heard it is not so good :(

Sent from my GT-I9300 using Tapatalk

[iPeel]

I've used it, and got some really good range. You're best flashing it with OpenLRSng, it's got a great UI for flashing and configuration.

https://github.com/openLRSng/openLRSng/wiki

I would try and use it with a mainstream antenna before you evaluate it with a turnstile. A Diamond SRH-771 on the TX and a sander-style on the RX would be a good idea.

[Big_Tone]

Gorilla glue spar in side 1.



Tape over gorilla glue to prevent having to cut off excess. Pushed it down a couple of times during foam up to keep smooth.



Weighed down plane on table to keep bottom flat whilst glueing.




Glued together.



Don't think I used enough in places. Might try and poke some more down the cracks.



Original layout plan as rambled in previous post was to have one removable batt on CoG and one at front. Glad I did the layout first, as it only seems possible to get cog with two batts up front. Still only just getting it and have done almost all I can to move stuff forward. Laminate will add more weight to back, so I might have to buy a go pro just for cog.

Also seem to have ordered big size servos :/ manual suggests micro size. Will use them anyway with slightly longer rods to try and get them forward for cog.





Weight pre laminate and before extra wiring, antennae etc.



Decided to put motor ply as far forward as poss with outboard mount coming off the back for weight further forward. Hoping it stays steady enough.



Recess melted in using knife and solder gun. Went round every coat hanger in the house with vernier calipers :s trying to find one that would fit. Ended up filing one down. Then I think it was too long as solder gun started smoking. That and molton styrene fumes stank out the whole house. Gf not happy. Have made a shorter one now but I think I prefer a flexible craft knife blade on its side where possible.



If the motor mount came with bolts then I lost them. These are a little long. Will just embed in the foam.

[Big_Tone]

Hole for turnstile. I decided to put a turnstile in rather than a dipole as on theory it should give even results. Will find out later if I get nulls :/


Cut a slit in the foam for turnstile leads. No glue required for this.


Coax cable coming up through wing from turnstile.


Made a combo cable to run all the rx wires to the APM out of old twisted pairs.


Embedded orange rx. Unfortunately the pins are straight up on it which means it needs a massive hole :/


Esc embedded. Cut a square of the heat shrink off for added cooling. Could always stick an additional heat sink on too if it's getting to hot.


Vtx embedded.


Starting to lam elevons


Lightweight filler is my new favourite stuff! Decided to give everything a very fine coat of it all down the wings. Did it really really thin so it only covers the deepest grooves in the foam, not perfectly smooth. Might avoid the cling film look when the lam goes on.


Batt doors from corrugated plastic. Made out of an old estate agent sign - a great source for the stuff. Some agents seems to use a finer board than others!


White on other side. Will hinge and then velcro down with 3m mushroom velcro stuff.



Bent up the belly board on kettle steam. When I glued it it actually could have done with a more acute curve right at the end. Also should have waited for it to fully dry before expoxying.


Lightweight filled the wing spar holes.

[Big_Tone]

Hardest bit of turnstile seems to have been the sma connector. I don't understand these. They seem to want to short out.  I think the one I have is also designed for thinner coax so had to create something using heat shrink and insulation from another bit of wire.





Flashing orange rx/tx is a dream with openlrsng config tool.

[Coyote]

Looking like a really nice build Tone