More sticks! Frank's Guillows Arrow RC.... Covid build

[tdo1]

Frank thanks for your  reply - I'm in Australia( I joined up last night so that I could ask you my question). I've taken some photos of where the plan was confusing me (not great photos but they should be good enough for you to see why I was confused).

You're confirming what I was thinking that if the wing is flat on the board then each tip can be the length of the measuring device off the board - I make it 39 mm you sound as though you made them 50 mm so I would have to decide whether to get a blade and change my 39 mm to 50.

With the the height above the board for the 2 centre sections Guillows seem to be suggesting in drawing 2 and drawing 3 that you use the same measuring device/stick of balsa as the outer dihedral - this is when the confusion began unless I'm misinterpreting something.

If I've got this right now I can use the 39 mm where I've glued or based on your actual flying get a blade and change  it to 50 mm and make the 2 centre sections 15 mm off the board?

I should add that I'm planning to use a receiver and motor and 1s Eflite battery from a UMX Radian so trying for ultra lite.
Unfortunately says my photos of the plan are too big
Peter
 

[Frank v B]

Peter,

Great to help out someone halfway around the world.

It will fly fine on 1S but may be more affected by the wind than my 2S set-up.

About the polyhedral, don't overthink it.  As long as there are 3 dihedral breaks (one at the center plus one at each tip) and they are equal on both sides it will fly fine.

The more polyhedral the sharper the turns for flying in a restricted area (indoors or small fields).

One thing I always tell builders is if you make one wing half to completion and make the same mistakes symmetrically (equal on both sides) it will fly fine.  Transmitters have trim tabs to take out building errors. 

Peter, feel free to post photos of the maiden flight.  Would love to see them.

Frank

[tdo1]

Frank thanks again for your help I might still be a while finishing it but I'll remember - just have to work out why the site doesn't like the size of my photos might have to do some compressing.
Peter

[sihinch]

Hey Peter - when you add a photo, if using an iPhone, at the bottom left of the photo, before you add it, you can select the photo size. Our website limits the size of files attached.

I usually select the "large" size photo rather than "original."

Hope this helps.

[tdo1]

test of photo size and quality

[tdo1]

a few more - I have some questions for Frank but I'll post some images first and see if that works I'm not using an iphone but sending images taken by my iphone and then saved to computer

[tdo1]

Hello Frank and Simon - I should have said originally that I've built my share of planes but they've all been FF with diesels so RC is fairly new to me.

Couldn't quite understand using iphone to reduce size of photos perhaps you are using your iphones to post as well? where as I'm taking photos with phone and then downloading to my computer - anyhow did a bit of experimenting and as long as I change size of photos to less than 1mb so 900 odd kbs seemed to work.

Got some good building ideas from this thread.Been so busy haven't had a chance to have a good read of the site but will get there.

Progress has been a bit slow not to mention the odd breakage and repair - I do have some questions which might be able to help me with so I'll just summarize what I've done and then ask my questions.

In no particular order - changed the fuse uprights and cross members to 2.5 x 1.5 mm - magnetic hatch for access to the brick and a bit more strength for the nose also 1.5 mm  balsa inserts at the front of the fuselage sides - brick is on a balsa shelf and a bit high but now has room underneath for a 1s battery with velcro  - landing gear is old fashioned cotton and ca on a thin ply frame not glued in yet - cockpit kept breaking so put the 2 halves in separately and glued them at the end - thinking about having a go at the fairing on the wing would probably look better.

Questions -
that's a piece of .8mm ply at the rear for supporting the tail - not glued yet - seemed like a good idea but .8mm will raise the horizontal stab by that much will that affect flight characteristics? - could just put some strips of balsa down the sides it's just that it's a very narrow section of the fuselage to try and glue to.

Should the nose have the round balsa part supplied and a stringer either side or can I just leave the nose as I have it? - I'd prefer to just leave it as is if possible.

Pushrods - I've got some .5mm ss fishing wire - with cross members installed will that ga support itself if cross members with small lengths of tube are installed at say 100 mm intervals? Not sure what a couple of you did?

Plastic covering will be interesting I've only ever used Aerospan/Polyspan which would probably shrink too much for this plane and possibly too heavy as well - found some plastic covering here in Australia which claims 36gm /m2 which sounded ok to me.

Peter - still 0 degrees C here of a morning but getting warmer during the day - 27C this week - here so I'm afraid that probably means the opposite for you.

[Frank v B]

Peter,

Great to hear from you again.
Answering your questions:
1) Stab: I glued the stab on.  Ply would be overkill.  Raising the stab by the thickness of the plywood will not affect flight.
2) the nose seems to be sheet balsa which is fine.  Leave the nose as you have it.
3) Balance: overall comment is that your plane, as did mine, will come out tail heavy.  Do everything possible to make the tail end light.  My motor weighs significantly more than yours yet it still came out tail heavy. I used a length of solder and wrapped it around the motor mount.
4) covering.  You have to use either the see-through covering as I did or the tissue supplied with the kit.  The shrink of any other covering will crush the structure when shrinking it.
5) pushrods- I used the smallest bamboo sticks bought at a Dollar store.  Then planed and sanded them down as much as I dared.  The ends are piano wire attached to the bamboo stick with dental floss and a drop of CA glue. Note: put the elevator horn on the top of the elevator so "up" elevator is a "pull" on the pushrod. You do not want "up" to be push in case there is flex in the pushrod.

Note- on several similar small planes I have used solid but thin piano wire and ran them inside aluminum tubes.  No flex, plenty strong, simple.

Your comment makes me feel a lot better about my build. I broke several stringers and ribs during construction purely from clumsiness.  The plane is strong once everything is held together with covering.

Frank

[tdo1]

thanks Frank you've given me a couple of things to think about - I'll report back later not sure when.
Peter

[Andy Hoffer]

Superb lighting on your test photos.

Bravo.

Andy Hoffer, TEMAC

[tdo1]

Hello Frank - Arrow is completed(finally) the plastic covering and I didn't get along all that well amazing how you can take some shots with an iphone at the right angle so that the plastic looks as though it doesn't have any wrinkles!

Couple of photos attached - just waiting for a non windy day to give it a throw in some grass over the road.

Weight is 75 gms with 2.5 gms of lead on the nose but I could probably add a bit more if I had to.

On the subject of C of G did you interpret the plan as about 10 mm in font of the TE - seems a bit odd I actually have about 20 mm but still seems odd. Used an online calculator and it's not giving me a measurement in mm but has it just in front of the TE.

The gap between my elevator halves is closer in the middle compared to the outside thinking about trying it as is.
Peter

[Frank v B]

Peter,

Great build!

re: CG- I just assembled mine and measured the CG ready to fly.  I flew it a week ago and it flew well but a bit tail heavy.  My CG was 1.25" from the trailing edge.  I suspect 1.5" from the trailing edge would be perfect.  It appears to be way too far aft (approx 60% of chord from the leading edge versus the usual 33%) but it flies well.

Keep sending updates.  We love to hear about your project.

re: test flying these models.  I start with a lightly powered glide to make sure of the CG is close.  Then power  up slowly to make sure the thrust line of the motor is correct, then power up.  Yours is much lighter because of the power system so powering up is not risky.  Mine loops, rolls and flies upside down.

The first flight is a great feeling of achievement.

Frank

[GuyOReilly]

@Frank v B concerning your comment about CG location :" It appears to be way too far aft (approx 60% of chord from the leading edge versus the usual 33%) but it flies well.
This model has a lifting tail and thus requires a more rearward CG than the average 33%.
The reason being the fact that the tail also produces lift, unlike a flat surface that would generate lift only when adding a angle of attack/incidence (another debate subject for another time...)

@tdo1 - Peter Love the covering.  Plane looks great and therefore should fly quite fine.   
Best of luck!

[Michael]

I saw Frank's plane fly. It flew nicely.