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Feb 14, 2019, 02:29 AM
B for Bruce
BMatthews's Avatar
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Are there servos that plug straight into Spektrum rx?
The Spektrum ones maybe? I poked some no name servos and a few Hi Tech servos into my Spektrums without noticing any issues. But maybe it was rubbing and I just assumed it was the pin sockets being tight? But mine all have one big opening instead of separate slots.

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then I just need to remember which way round to insert them
Go by the wire colors. Your picture shows what seems like pretty good teeth for aligning the connectors. But I'll bet it does not take a whole lot of pressure to insert one backwards.

The middle wire is always positive power. And the two outer wires will always have one lighter than the other. Black and brown are popular for the ground color. White yellow or orange seem to be popular from my collection of random brands for the signal line. And the signal line always faces in towards the center of the Rx for top fed connections. If you have Rx's that are end fed check the labeling. But I'll bet signal always goes to the top side brand name label and negative to the blank bottom side.

I'm in the same boat. So many different brand servos with so many color wires and alignment bevels that do little or nothing. So I always check the wire colors now regardless of brands.

Thanks for the Bangood link on the wheels. I'm going to order up a few pairs. Those are WAY lighter than anything I've seen around. Just crazy light in fact.
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Feb 14, 2019, 04:17 PM
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OK all sorted now thanks! After some filing and sanding all plugs now fit Google tells me this is not an uncommon problem with some Spektrum receivers, particularly the AR610 which has quite narrow slots and corner splays fatter than on most JR plugs (except presumably Spektrum). However nothing that sanding/filing can't fix. Also all clear now on which way up

BTW those "Model Aviation" balsa density charts are a great resource, many thanks for the link. I'm now off to buy some "lighter" 1/16 sheet for the fuse sides with more confidence as to what weight to look for - if I've interpreted the chart correctly something in the order of 13-14g for 100 wide sheets.
Feb 15, 2019, 12:14 AM
B for Bruce
BMatthews's Avatar
Did you find any metric charts? I forgot that NZ would be needing metric density tables. Oopsie

The metric table I found HERE says that for 1.5mm x 100mm sheets 13 to 14 grams would be wonderful. And a piece of 22 to 24gm wood for the doublers perhaps.
Feb 15, 2019, 05:12 PM
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Thanks for the metric table Bruce, that completes the set although the imperial tables are fine for most common sizes, which have reasonably close metric equivalents (except maybe 1mm and 2mm, which fall between imperial sizes ). The only reason I used 4mm for the fin rather than 1/8" (3mm) was that I didn't have any decent 1/8 around at the time! However we can still buy imperial stock locally and the 1/16" I have just bought is Bud Nosen "made in the USA". I didn't quite manage 13-14 gms but found a couple of nice 4' lengths at a little over 20 gms each so that's 15 gms for a 3', length close enough? I have another sheet at 23 gms that I will use for the doublers, This is my first build to take such a considered approach to weight (and I now know why the gliders I built as a boy didn't fly that great...)

Now to cut out the sides, and I see both will fit on one sheet. That's a win/win - the 4' lengths were cheaper than the 3' lengths (old stock I think)
Feb 15, 2019, 09:10 PM
B for Bruce
BMatthews's Avatar
Yeah, that's more than close enough. Same with the doubler sheet you found.

Doing a lot of free flight when I started out made me into quite the "weight wienie" as my frequent harping on that aspect in post after post will attest. And in truth there's a couple of times I wished I'd used heavier wood. One in particular is downstairs right now awaiting some rebuild time and which likely would have survived the cartwheeling if I'd used stronger balsa to start with. But on the whole building lightly has served me well.
Feb 24, 2019, 11:32 PM
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Thread OP

Knock-off landing gear


Fuselage sides, doublers and formers have been cut and ready for assembly but I'm hesitating over that landing gear arrangement which is designed to "knock off". The landing gear wire sits in a groove in a hardwood bearer and is held in place by rubber bands looped onto holding pegs on either side. Seems to me the wire is more likely to pop out of its groove than stay in it most landings which could get frustrating, particularly if the rubber bands keep pinging off. I'm inclined towards a more rigid fixing e.g. bind the wire to F-2 or to a ply bottom plate, but given this is very much a learner craft maybe ease of knock off isn't such a bad thing

Has anyone used this sort of landing gear attachment shown on the drawing and did it work out OK? Thoughts appreciated.

Bob
Feb 24, 2019, 11:37 PM
I'd rather be flying.....
JeffMac's Avatar
Hi Bob -

MA is looking fine........ Knock off gear : Yes, Ken Willard used that style on several designs. I have used it on Schoolmaster and Roaring 20 (25) and other models i have. It works well for me....

Best regards,

jeff
Feb 25, 2019, 03:29 AM
I like real wooden aeroplanes!
Sundancer's Avatar
I had a Bill Winter "Pal Joey" which uses an identical set-up for the gear. This was back in the escapement days, the model was rudder only with MacGregor S/C gear, a Compact escapement and TD.049 power, so no elevator to flare the landings and the undercarriage mounting worked extremely well in absorbing the landing shocks, as long as the rubber bands were TIGHT it didn't jump out of the groove but pivoted back sufficiently to absorb even quite heavy impacts. Having said that, many years later when I built the Winter Miss America it was as a rudder/elevator model (but still with a TD049) and I used a bolted on undercart on this one as we flew at the time from a tarmac runway and I could, of course, flare the landings. For what it's worth, if you are going to be flying from a grass runway I would be inclined to use the original set up, even on an RET electric model.
Feb 25, 2019, 04:19 PM
Registered User
Long ago I used this method too and I support SD's comments. I would add that unless a heavier than usual section of wire is used the wire gives on landing so as to scrape and bruise the sides of the fuselage.

For many years now I have used whenever possible the system you may be able to figure out from the photo. It would suit your plane and in fact is easily retro-fitted to most planes, requiring only a hole for the skewer in front and the aluminium tube behind. Little or no bracing is needed because the stresses around the mounting points are not high. The fore and aft section of wire between the skewer and the tube acts as a torsion bar absorbing landing shock and the rubber band (should be tight!) dampens rebound.

It is a little more difficult to bend up because the bends are in three dimensions, but you can usually get away with wire one size smaller.

It's going to be a really nice little plane.

Afterthought - the bend where the wire enters the tube should be slightly greater than 90 degrees so that the rubber band has to draw the u/c into the fuselage side; otherwise it tends to work its way out of the tube.
Feb 25, 2019, 06:42 PM
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Jeff, George, Footrot - thanks for replies and insights, which gives me a better understanding of how the groove/band attachment works and agreed "knock off" is the way for me to go (I will be flying over grass and a complete beginner at RC!).

Footrot, I like your approach, many thanks for the pic.

So "knock off" it is but now need to decide which approach
Last edited by RobtP; Feb 25, 2019 at 06:50 PM.
Feb 25, 2019, 09:13 PM
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Foxtrot"s landing gear would look perfect on the Miss. I'm going to steal it for a future build.
Mar 10, 2019, 10:12 PM
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Agree with your thoughts there Remitt, that's the way I'm heading. Main reason is that the wire building will be a little easier for me and I won't have to groove a piece of hardwood, which I could easily make a messs of Thanks for the suggestion Footrrot!

A little more progress. I partly re-built the stab by cutting back the inside of the leading and trailing edges and tip pieces and replacing the ribs with lighter wood. This has reduced the weight of the stab by 3.7g (now 9.6g). Not as successful as Sideslipper's effort, but think I will leave it at that as any lighter I'm likely to starting breaking bits. Still potential to lighten the fin a little by cutting out the centre section and installing some "ribs", along the lines of Bruce's suggestion.

Continuing to find little discrepancies between the build article and the drawing. Bill Winter must have been looking at a different version of the drawing when he wrote the article, but it's not a problem and helps me to think thing's through.

Next I will finish off the nose area, by first gluing on the firewall with light fibreglass at the side joins behind for additional support, as the sides thin down at that point, while contemplating the servo and control rod installation. The Du-bro lazer rods I have used previously seem somewhat heavy for this size model, so thinking of .032" piano wire (which I have Du-bro connectors for) or 1.5mm carbon fiber rod (if I can find connectors to fit). Will .032" wire be stiff enough, if supported at the formers?

Bob
Mar 11, 2019, 05:01 PM
Registered User
Glad you're going to try the detachable u/c RobtP.

The only problem I can forsee is getting the toe-in and camber right which can require some tweeking. Also the wire should stand about 3 or 4mm out from the fuselage at the skewer/dowel with the rubber band pulling it flush to the fuselage side to stop it popping out of the tube at the back

Will be a really sweet little model.
Mar 11, 2019, 10:40 PM
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Thread OP
Thanks Footrrot. That's a little cutie in the pic

I'm planning to insert a little piece of 1/16" ply below each dowel where the wire will be pulled by the rubber bands against the fuselage, as I figure there could be some wear at that point. The fuse sides already have cut outs for the hardwood bearer required for the original scheme, so I will just fill those in with the ply.

Regards
Bob
Mar 20, 2019, 08:26 PM
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Thread OP
One question Footrrot - do you put any special strengthening around the tube? I've tried to figure what might happen in a really hard landing, with wheels pushing back and upwards, The wire might pull quite hard against the tube?? Thinking a little strengthening inside where the tube passes through the sides might be a good idea.

The nose is now shaped. I like the Miss A nose, it has a nice length, which should be good for balance. I will cut through the top block a little ahead of the windscreen position to allow part under the windscreen to be fixed and the rest removable for battery access.


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