Chris Walby

If its a servoless retract it should have stall protection or as said previously they are small motors inside so should not have massive current draw (next to nothing when sitting idle). If its the old retract driven by a servo then yes if the UC jams/binds the stalled servo is going to try and achieve its commanded position until it burns out. Good practice to put UC on a separate battery if its not servoless. Just look at how many ARTF's are out there and which ones have a separate battery for the UC? Fuse is a naff idea as you are going to have to test it ..most likely to destruction to find the point when the fuse will operated when jammed, but not operate when the retract is operating under flight conditions. Fuse too small and you will probably have to land with the UC half up/down. That's why the servoless UC have stall protection that self resets on next cycle! Remember a 1A fuse does not operate at 1A ! IMO making sure that the wheels wells are large enough for the wheels + a little clearence and that nothing binds is the most best way of getting them to operate reliably. Some people cycle the UC after each landing just to make sure nothing has been bent or come loose and is likely to cause a problem on the next flight or a good visual inspection when back at the bench (with the battery isolated).

Speed Air, first electric then post B cert it just had to be...Laser 70. Air frame was £70 new with the idea that if I broke it then another would be cheap. Pilot error caused its demise and I fell off my perch when I went to replace it due to cost! The Laser 70 then went in an Acrowot where it still resides, great model. And yes the colours are correct...it was flown that much that the red went light pink and the plasticiser had been destroyed by the UV hence the extensive patches. PS both wings had twists and people would comment that the ailerons were out of trim, but they were for level flight!

I have a Fluke digital multimeter (auto range, all bells/whistles etc..) that I had as an apprentice and am now retired so its 42 years old and still works as it first did out of the box. A club instructor flies one of my models (takes me to launch the very under powered high wing loaded model) using a DX8 gen 1 on DSM2 with no problems and he flies really big circuits (has very good eyesight!). One of the factors might be how the TX has been treated in the past, recently someone left his TX out in the rain, scrambled screen and odd things happening with the scroll wheel. Dry it out and use use it, really?

Martian, You have got this far and with all your time invested its best to finish it off as I am sure it will fly well in the end. As for mine the fuselage is all wood, perhaps the builder got a good deal on hard balsa as it tough as of boots. I can't get to the fuselage to take the servo cover off the elevator servo and see what the horizontal stabiliser is made of, but non of the tail is detachable. this makes it a right pain to store and transport as it takes up loads of space! I have heard (right or wrongly) that Don Smith are good scale designs, but need a lot of forward planning and head scratching to actually build. I have been holding off on a major repair and complete build of a kit because both have foam veneer wings and I don't know to mate the nacelles or join the wings (in a detachable way). I have only been at this hobby less than 10 years and am surprised with the way some designs get away with minimal construction techniques (ASM Tigercat) or outside toilet for others. I give all those that modify/rescale designs massive credit

Thanks Martian, On the plus side Its the right wingspan Wings are foam veneer Have to check the tail feathers for material They quote max weight 55 lbs (25Kg and mine comes in at 21.7 Kg wet) Where mine differs Fuselage is balsa Nacelles and cowls are balsa I think you are right and someone has ditched the glass fuselage (I have a Power Max Mossie and its so tail heavy it needs 2.7 Kg of lead to get it to balance!). So have made the nacelles and cowls while at it. Lets face it if they could knock off a fuselage the cowls and nacelles would be easy! Or perhaps they copied Giant Scale Twin and made it all themselves. Anyway less of this and more of how you are getting on with your build?

Payneib , do this one first! a nice starter for the winter season + I like the colour scheme 🙂

Good job there and really starting to look like a big cat. Well done there. Were you aware if any other Tigercats (116 inch) that were not Don Smith, but with foam veneer wings and built up everything else? Still trying to find out where mine came from?

Update! Worst case with one battery, one UBEC and the volt drop of the meter on one servo input lead Supply voltage 5.44 V Quiescent current 1.08 A Quiescent power 5.9 W Loads of stick bending in every direction while deploying flaps and gear doors achieved: Max current 4.78 A Min voltage 5.09 V Notes I can adjust the UBEC output voltages to 5.60 V which will give the diode supply suitable voltage head room The total above is shared across two RX's so the individual loads on the UBEC's will be less, but should a UBEC/battery fail then one UBEC can easily cope with supporting both RX's I would need two FRsky devices to achieve dual redundancy and 4 batteries, a rather complex solution IMO that can be achieved by the use of two diodes. If I could use only one RX then Spektrum do Power Safe RX's (with dual battery inputs as standard). Thanks to all for their positive contributions. l

The in line was going ok until the crank broke...the problem with multi cylinder engines is the working cylinder/cylinders will continue to smash the bits around making a right mess. How long to take the rocker arm off, valve collets and check the valve, but its up to you. Break the 310 and you won't get another one! Just very surprised the piston valve clearence is so small for a pushrod engine, unless it was a lot of play.

Exhaust valve? A bit surprised that the valve timing is that aggressive for the piston to chase valve home (been there, done that!). Interesting to know how close the piston is to the cylinder head (its only just off a flat top piston)? IMO more likely a sticky valve in the stem and the piston is helping the valve home. Check valve springs and the valve in the guide while its all apart 🙂 You'll be able to check the valve stem at the same time. No fun when the head falls off the valve stem on a multi cylinder engine.

While I think of it Any advice on where to get the various paints from? manufacturer and colour please Supplier of the aluminium tape used for the canopy? Any details of the tail wheel used? or I'll just have a hunt around in my spares bins! Cheers

Play major catch up with this one, but making good progress in the last week or so from part assembled fuselage and wings that needed sanding! Wings sanded, copied Ron's suggestion and sanded the centre LE back a bit to get a less pointy LE Aileron and UC pockets cut + sires laid in Wing dihedral and joined + wing tips fitted (just need a bit of finishing Fuselage rear balsa deck glued in place - Q1 Rear fuselage triangular parts fitted and sanded, Thanks Ron for the tip Hopefully I'll get on with the wing to fuselage tomorrow and thus the front of the fuselage tomorrow Questions the fuselage rear of canopy to fin seems thinner than the drawing. Was that left as is or a little bit of balsa added to make it a bit more pointy? Is there any profile to the wing tips or just blend the corners off and follow the plan radius? I come across some designs where the bottom of the tip stays flat? Has anyone modified the retract leg where the push on wheel retainer is located, my wheels (the wheel retainer) touches the bottom of the wheel wheel. I could pack the UC servo up or shorten the wheel spindle

"See me doing that live" and with all due respect I don't think I could keep up with the build speed especially if Eric gets on board it would be finished in a week! I am back on the Tempest build and only a couple of minor comments regarding the VLOG for that. The build of the fuselage and wing simultaneously makes it quite time consuming going backward and forwards trying to find the VLOG that covers a part of the build I am currently stuck on! Bits of the build that are missing. E.G. with the fuselage one minute you were pinning the rear deck and the next its all finished back to the tail feathers section (I'll raise my Q on that thread). Perhaps a Q and A with Ron in the shed would be a bit of fun, but might be tricky it does not head off at a tangent or rabbit hole discussion.

It was an extra slim twin, but not to worry as I have another, although I may well convert to electric. Photo prior to the abrupt arrival of terra firma .

Or just don't have something that weighs loads, has high wing loading and comes in like a steam train or tip stalls aggressively. IMO why the FW 190 works so well, it has none of the above traits

Hoping its not on the 9/10 Aug25.

For simplicity and its pointless showing the negative wiring as its effectively all common up anyway. Just as I have not shown any of the servo wiring including signal wiring. Doe this help you.

Thanks Brian, yes they are simultaneously powered so the idea is they share the load (as in the first example configuration). They plug into the RX via standard servo plugs hence the reason for two probably due to the rating of the servo plugs or the ability for one UBEC to power two RX's. I could do some tests with one and both supplies connected and see what the peak current and voltage is. Each switch/UBEC is rated at 15A, 20A peak and bearing in mind if the voltage sags in the second example then current will flow from the other UBEC. If one UBEC fails I'll be doing a Bob Hoover "If you are faced with a forced landing, fly the thing as far into the crash as possible". It should be flyable on one RX, but if its a case of a critical alarm and put it down as soon as its safe to do then the latter option gets my vote. The model has air retracts so a binding servo is unlikely although it does have digital servos on some of the control surfaces, it will not be flown in an aerobatic style!

There are dual powered RX's, but they are quite large + I'll end up with 4 RX batteries or 2 Rx batteries and duelling up inputs or mini power servo distribution boxes. The latter are 3 inch by 4 inch and hence quite big + again its either 4 or 2 doubled up RX batteries. I like to keep it simple as the less complex and components in the model then the more reliable its likely to be.

SG Mossie and this years bike clip moment, Tigercat (still from Ron's video)

Brian's Vulcan (I am just the keeper), pilot Dave bringing her back after a successful mission/take off. Another general shot, both not by me! Its weight and wing loading are off the normal chart, but with a 25Kg bungee and dolly she gets away..most times!

I have a model that requires 2 RX's and have selected 2 ten channel devices. These are powered by to switch/UBEC's where each switch/UBEC has two output leads. The normal practice is to connect each UBEC output lead to opposite ends of the RX output servo bus. Example A As the model requires 2 RX's the thought crossed my mind that the outputs of each UBEC could crossed with the RX's with the benefit that should one RX battery or switch/UBEC fail then the other will just take over. I don't like the idea of two devices (UBEC's) outputting onto the same RX servo bus as one will always take precedence and discharge one battery first so I came up with the idea of using a suitable diode or two. The advantage is that the TX/RX can be set up to detect the slightly lower supply voltage (0.6V) and generate an alarm. Example 2 What's the considered opinion or views of the esteemed collective? I don't think we need to go into the pro/cons of battery technology/connecting them together as that has already be covered elsewhere.

Best try and avoid if you can please The rest of August looks clear except.

For fuel to get out, air must be getting in. If its a non pressurised vent the plug it with "Remove before flight tag) so you don't forget or if its exhaust pressurised the pull the vet off the exhaust and tag the same. IMO the fuel lines are not large enough ID to allow fuel in one direction and air in the other.

What engine are you using and a couple of photos would be good?