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Seagull Dual Ace Laser Build

First build with IC

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Chris Walby09/03/2018 21:53:36
487 forum posts
71 photos

Progress update cool

Tinkering along with aileron linkages, U/C fixings and prop clearance (looking at just over a inch although it was tricky hold lots of loose bits so I'll do it a gain once the nacelle boxes are finished and fixed in.

While I was at it I had a play around with the carb and exhaust orientations to see if I can obtain easy access to both carb needles .carb position.jpg

Those with OCD won't like the fact that the carb and exhaust are at different angles, but its works for me as both needles will be outside of the cowl and accessible without me touching the exhaust to get to one!

Other progress was making the spinner back plate spacers and gluing the nacelle bulkheads in. This will allow me to work out where the throttle servo can go and recheck the prop to ground clearance.


Chris Walby14/03/2018 22:08:56
487 forum posts
71 photos

Update time again! smiley Although progress seems to come to an all time slow I think I am making so headway!

Nacelles are more or less finished and now just need gluing into the wings, then a coat of fuel proofing and they will be complete.

Pilot and crew ordered form HK plus a fail over regulator (I really can't see the point of a switch as it just another thing to go wrong) and was just going to do a same as the Speed Air. Plug the battery into the UBEC and lock the canopy down, then control checks and start the engine. I'll see where the C of G ends up and can always go with a couple of RX batteries if I need a bit more weight crying

Lastly on the subject of overly long nylon wing bolts I went through my dad's nuts and bolts collection only to find some UNF cheese head screws. Small washer and some epoxy hey presto these should do the trick!


I really don't know why Seagull are using UNF, but perhaps that's for another thread?

PS I ended up with the carbs vertical again, OCD now at a new state of karma wink

Chris Walby16/03/2018 21:14:24
487 forum posts
71 photos

More slow but sure progress, honest things will get more exciting soon.

Nacelle boxes are in and they just need fuel proofing before everything can be fitted back in, Saturday job


Fitting up of the nose for the C of G check

front bulkhead.jpg

List of things to do:

  1. Collect tank No2

  2. Cockpit crew – on order from HK

  3. Plumb clunk line on No2

  4. Make and install vent pitot tube

  5. Aileron leads to servo

  6. Mount RX, switch/BEC and batteries

  7. Make spinner adaptors

  8. Centre aileron servos on RX

  9. Nose, cutting wheel opening and fixing screws

  10. C of G check

  11. Control surface throws and throttle settings

  12. Club inspection

  13. Fly

Its not looking too far off being complete (thanks for the advice chaps) and we will see how it goes with a pair of Lasers in it!


Martin Harris17/03/2018 10:27:28
7634 forum posts
190 photos
Posted by Chris Walby on 14/03/2018 22:08:56:
I really don't know why Seagull are using UNF, but perhaps that's for another thread?

I doubt that another thread would be needed (although there is already at least one) to conclude that Seagull see their major market as the USA, which persists in using the more flexible imperial system. If only the human race had evolved with 6 digits on each hand it would be a no-brainer that we'd all be using it...

Edited By Martin Harris on 17/03/2018 10:45:00

CARPERFECT17/03/2018 19:31:36
354 forum posts
5 photos

Chris Walby. Not sure what radio you have. But i had my Dual Ace on Futaba 8j. Each engine on different channels . the 8j has 6 trim switches, most only have 4. This enables you to adjust each engine so they are in harmony. I also had the rudders and engines on a mix, operated by a switch.(ground only) When i applied right rudder the left engine would increase in revs and vice versa. It helps turn it on the grass. I also fitted two rx switches the second was in between one engine and the servo, ( must be 3 wires though) this allows you to start one engine, get it tuned, set the revs to just over tick over , then turn the switch off. now start the other engine and tune. when happy turn switch back on. You can see me do it on my link earlier on this thread.

CARPERFECT17/03/2018 19:34:40
354 forum posts
5 photos

You Tube Seagull Dual Ace x 2 SC52 FS engines

Chris Walby17/03/2018 22:07:47
487 forum posts
71 photos

Carperfect, Thanks for the information, I have an electric twin with no rudder where I mixed rudder into throttle, but had some grief with and RX that would not throttle down one channel (not the throttle channel) on loss of signal so I used a lemon RX. The model passed range checks and flew once okay and crashed 3 times. I thought it was me, but the last time it crashed it didn't launch the lipo out of the fuselage and the RX was flashing. Its sitting in the naughty corner and I have a feeling its something to do with the "electrics". I have my suspicion as to what it might be, but I want conclusive evidence which will take time. Its flight envelope was very disappointing as well so might just put it down to experience!

I am looking to keep the Dual Ace as I simple as I can (the less things to go wrong) as I am new to the IC side of things.

cymaz18/03/2018 06:05:59
7634 forum posts
981 photos

It’s an utter pain to get the idle end points to match as the linkage is not easy to get at. I posted the Tx mixes I used for my Futaba 9c on page may not help at all if you use another Tx make.

Chris Walby18/03/2018 21:46:07
487 forum posts
71 photos

Great news !! smiley

Its all coming together and today was the first go at C of G. Spinners, props tanks and RX batteries (not the nacelle covers) and C of G is good at 105mm back from LE! In fact I need to move the batteries back to make an easier method of install/changing plus the RX can sit on the middle tray which will help even more!

News getting better!

Weigh in again without nacelle covers comes in at 4.789 Kg and Seagull AUW is approx. 5 Kg so those big Laser 70 are not weighing it down cheeky

Last be not least with the modified nose wheel gear and bigger wheels I have 2 inches of prop clearance which hopefully will be enough for our patch on the basis that it is tri-cycle so should not tip over.

Thanks guys for the advice, its been a big help and now to scratch my head around setting the throttles up with separate trim.. dont know

Jon - Laser Engines19/03/2018 08:34:35
3834 forum posts
149 photos

In the interest of keeping it simple chris i wouldnt do anything complicated with the throttles. Just use a y lead and take a little time making sure the mechanical setup of the servos is as close to identical as possible. If small adjustments are then needed to the idle rpm of one engine, or more importantly its half throttle rpm, you can adjust the throttle rod length by unscrewing the clevis.

The two engines i sent you are a matched pair and as close to identical as i can make them. You shouldnt have any trouble.

I dont recommend throttle/rudder mixing either as it can produce huge yaw if you dont get your curves right. If its only for taxiing then ok mayb, but certainly not for anything else.

I have owned 5 twins and a 4 engine model. All of them had y leads and no mixing and flew without any trouble for many years

Edited By Jon - Laser Engines on 19/03/2018 08:35:32

Chris Walby19/03/2018 09:06:52
487 forum posts
71 photos

Hi Jon

I think the servo and throttle arms will both be outside of the nacelle cover so can be adjusted at initial set-up plus as the rudder and steering are on separate servos so I could do something there if taxing is an issue.

The train of thought was more along being able to adjust the tick over separately without resorting to mechanical adjustments. The experience with the rudderless electric thing was a bit weird as it yawed around the C of G rather than turning in (didn't look very scale and gave the impression if pushed it might spin!) then again it didn't give me much time in any department apart from the long walk with the bin liner 3 times! (its in the naughty corner awaiting for more time and will perhaps).

Anyway back to the throttles and the RX I have in mind may not allow for separate throttle channels with throttle cut in both which will mean a Y lead and keeping it simple (suits me!).

Main thing is to have it ready for the "better" weather laugh

Jon - Laser Engines19/03/2018 09:50:34
3834 forum posts
149 photos

Dont get too caught up worrying about the tickover. You fly at much higher power settings and its more important to have the engines together at your normal flying power setting.

What you could do is get all the servos in stalled and do a test run with the servos on a y lead. See how the engines behave, if a small mechanical tweak is all you need, and then if its all as you would like you can save the time spent on the more complex setup.

Alve Hansson20/03/2018 09:39:36
22 forum posts
6 photos
I have a dual ace kit that I planned to build now this spring. Engines become Asp 52 FS and I will use Microsens Glow 4 L for onboard glow.
Will follow the thread with great interest.smileyyes

Edited By Alve Hansson on 20/03/2018 09:40:16

Edited By Alve Hansson on 20/03/2018 09:40:38

Chris Walby20/03/2018 11:29:34
487 forum posts
71 photos

Alve, All the best with your build and please keep us posted on progress.

I am new to IC thus wanted reliable engines and Laser are local with great support from Jon. The other thing was that some of the Dual Ace builds needed lead in the front to achieve correct C of G where I have not needed to add any (my C of G is forward so batteries etc are rearward).

Plus Lasers don't need on board glow or pressurised tanks so the install is simple laugh

There is one last minor thing....I want to really run these engines in before they are moved to another airframe I have in mind wink but that's for another thread.

Chris Walby28/03/2018 16:28:30
487 forum posts
71 photos

Been a bit busy at work and with some decent weather (nearly another 1/2 gallon through the Speed Air Laser!) progress has slowed.

After 10 hours at work Sunday I drilled and tapped the spinner engine adaptor nut M5, doh original was M3 and needed to be M4. Plan B and stood in front of the lathe and made two the right size.

Dremeled the nacelle cowls and it seemed to go okay, still need to fit the cowl spinner ring and a couple of screws down the sides to finish off.

Second thoughts about the throttle linkage and have come up with a better way with a z bend and a metal clevis.

Plumbing and control throws at the weekend with just the crew to finish things off (plus a load of other stuff).

Then it will close to running the Lasers up for a few ground runs.


Chris Walby08/04/2018 22:14:19
487 forum posts
71 photos

Tinkering with the electrics as I'll go with dual RX lipos and a HK switch that will supply from either battery, so just need to sight the switch and connect things up.

I though I was nearly there with the nacelle cowls and with one finished though I was about there, but NO!

Having doubled checked measurements I can't get the two nacelle cowls to overlap without hitting the prop spinner. If I pull the cowls together at the spinner end, either the cowls won't sit flat (like getting creases in them) or the curved flange git of the cowl won't sit flat on the wing.

Any advice welcomed ?

I could pack one side of the nacelle out a little to stop the creases or trim the flange section of the nacelle flanges to get it to site back against the wing....?

Chris Walby10/04/2018 21:26:02
487 forum posts
71 photos

Well I got the nacelles to fit, can't say I am very happy about it although there have been some valuable lessons learnt as in the sequence of cutting, fitting and then drilling holes in the wing.

Pilot and crew turned up and the dual supply RX switch/UBEC and that's only because I needed a couple of small RX batteries in the back of the fuselage to get C of G. I don't think I'll bother again with a switch (the Speed Air I just open the canopy check the tank is full and plug the battery into the UBEC), ready to go.


The rest of the crew will need dark glasses the way I fly laugh

With a couple of RX batteries on order it will nearly be ready for pre-flight checks, noise test and some ground runs to gently run the engines in.

I don't think there is a lot to add apart from a big thank you to all the guys that have passed on their help and experience over the build process, cheers.

cymaz11/04/2018 01:04:20
7634 forum posts
981 photos

Can’t remember for the life of me but is there a bottom and top to the nacelle halves?

Edited By cymaz on 11/04/2018 01:04:55

Tom Thomas11/04/2018 03:45:25
315 forum posts
207 photos
Posted by Paul Marsh on 24/02/2018 12:16:34:

I have a C160 Transall and one engine quit on take-off, no-where to go and kept full power and full rudder to clear the hedge, cut the throttle as it flick-rolled, but leveled off and landed heavy in the field - the only damage was a bend wing tube and one wheel came off.

Twins are a great way to expand your skills - it would be boring if everything was easy. Engine-outs have killed full-size pilots, so not restricted to models. This is a classic ca

Edited By Paul Marsh on 24/02/2018 12:17:01

Paul, posting a vid of death and comparing it to our hobby? A "classic case" ?  Non comparable.......

Edited By Tom Thomas on 11/04/2018 03:48:12

Tom Thomas11/04/2018 03:59:24
315 forum posts
207 photos

Children died in that incident... gets me when children are involved in any life limiting situation.

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