ACE All Star Biplane

[rockyboy]

After getting the ARC Nu-Bee 2 all ready for maiden flight (and waiting on a pinstriping brush to finish up the paint job) it's time to make some balsa dust!

I found a classic ACE All Star Biplane kit at an estate sale of a local modeler. This plane was designed in 1972 by Roman Bukolt and published in Radio Control Modeler magazine the design was later kitted by ACE as it used their constant chord foam wing (not the tapered one identified on the box). Since Willy Nillie's hasn't started laser cutting this classic 1/2A design yet I was thrilled to get one of the vintage kits complete with foam wings.

Luckily the plans for the All Star are available on Outerzone for reference - cause the ones that come in the kit are not full size!
https://outerzone.co.uk/plan_details.asp?ID=1355 Reading over some notes from other builders it looks like I should shoot for 32 ounces max - 900 grams in metric - so I'll need to dig around my motor pile to see what I have that's appropriate.

The plans are also curled up pretty solidly, so I put them under a sheet of glass (tempered desk top picked up off the side of the road) and started arranging all the parts.

There are text instructions in the kit, so with lots of reading and re-reading, I'm starting off slowly. First up is gluing in the nose doublers. The kit says glue in all three doublers, but I'm going to do them one at a time in hopes I can keep things aligned better that way. Below is a piece of plastic keeping the glue from attaching the two sides of the fuselage together at the top while the nose doubler dries. Next I'll glue in the firewall and second doubler.

[Edit: Want a sneak peak of how she looks all finished? Of course you do! ]

 

[Hai-Lee]

Another FTFC 20 challenge entry?

Have fun!

 

[TooJung2Die]

An interesting mix of old and new. Foam wings and "precision bandsawed balsa and ply parts". I love biplanes. How they look and how they fly. I'll be watching.

 

[rockyboy]

Another FTFC 20 challenge entry?

Have fun!

Maybe - but since it already comes with foam wings isn't that cheating a little bit?

An interesting mix of old and new. Foam wings and "precision bandsawed balsa and ply parts". I love biplanes. How they look and how they fly. I'll be watching.

I'm really impressed with the quality of the cuts on this - they aren't kidding with the "precision bandsaw" claim - way better than the die-crushed kits!

The motor drawer coughed up a Hacker A20-20L motor that will pair with a 9x5 prop on 3s to put out 165 watts and 30 oz of thrust - so if I come in at the recommended 32 ounces / 2 pounds of weight, I'll be in the 80 watts per pound range and 93% thrust to weight ratio for a nice sport flier. A 9x6 is also an option that boots the wattage to 210 if I need more excitement in the power setup, but I'll need to be sparing with the full throttle setting

Of course if I can come in a little less than the 32 ounces, that wouldn't be a bad thing either. A lot of the material that's in the plan is heavier than needed for a brushless motor that isn't trying to shake the plane to pieces like a nitro motor. I started to think about that well after I put the glue to the nose doublers last night though... thinking I'm going to take about half that doubler off, and start reducing weight in other places as much as I can too. I saw another build where they cut out 8 lightening holes in the fuselage for a 1.6 ounce weight savings - which that builder didn't think was worth the time, but personally I think is a pretty good deal. If I can find two or three more savings opportunities like that she'll be very light indeed!

I also have a spare set of ACE foam wings - I need to check if they are the tapered or constant chord. Either way, I'm thinking of installing ailerons in one of these wings so I can have a RET or RETA setup depending on which wing I rubber band on. The 3 channel configuration would be lighter of course, but the ailerons add a lot more aerobatic fun!

 

[Piotrsko]

I miss my bipe...... I had a tapered wing kit ailerons on lower wing only. Powered by OS max .19 kinda a rocket for the day. Bank & yank only wasn't room for the tank, battery and 3 standard servos. I think I miss the wing cores more

 

[rockyboy]

I miss my bipe...... I had a tapered wing kit ailerons on lower wing only. Powered by OS max .19 kinda a rocket for the day. Bank & yank only wasn't room for the tank, battery and 3 standard servos. I think I miss the wing cores more

Do you remember what dihedral you set it up with? I expect the design recommendations are fine for a RET setup, but thinking it could benefit from a straighter wing with ailerons.

 

[Piotrsko]

Do you remember what dihedral you set it up with? I expect the design recommendations are fine for a RET setup, but thinking it could benefit from a straighter wing with ailerons.

Top wing had recommended dihederal or more, probably more, bottom was flat. Common in WW1. Had a heck of a time balsa covering the upper wing first, so had to salvage the job. Think I lost an inch of span. Didn't have cheap foam safe adhesives back then. Was a bit barrel rolley as a result, but not bad. Modern equipment with aert, I'd still do it that way. It would probably be better with a working rudder definitely something that would swap from 3 to 4 channel easey peasey.

 

[rockyboy]

Firewall prepared - blind nuts and motor stand-offs installed. Firewall isn't the neatest looking work, but it's plenty sturdy and will be entirely hidden in the end Also cut holes for the servo rails before gluing in the rest of the side doublers.

Then it was time to glue the fuselage sides together with the firewall and full width bulkheads. The hatch block is sitting in place to keep things square, used thin CA sparingly to tack things together without gluing the hatch down. This picture was taken moments before I realized I forgot to install the servo rails and I had to pull things apart a little bit to slide them into place

Then I pulled the hatch block off, stood things up to use some building squares to keep the sides straight, and glued the bulkheads and servo rails in properly with Superphatic.

Final bit last night was gluing the back of the fuselage together and then installing the rest of the formers.

I've been thinking a lot about the hatch modifications that will be necessary to convert this from wet fuel to brushless. The stock design has the hatch permanently glued to the cabane struts holding up the center of the top wing. This means that to take the hatch off, the top wing will have to come off too, and with the way the outer cabanes connect to the lower wing I just don't see this as being a simple task. This is fine for wet fuel engines since accessing the fuel tank is not a common task, but I plan to put the battery where the tank would go.

So I'm planning to split the top hatch into two pieces. The back piece of the hatch will connect with the wooden dowel to the cockpit former and the same nylon hatch screw - just relocated from the firewall back to former F2 that's right in front of the cabanes. This way the back hatch can be unscrewed and wings disassembled to access the servos, but usually left in place.

The front hatch piece will sit on some new rails I'll install on the fuselage sides and cover the battery and top of the motor. I already set the firewall a little higher than the plans and slotted the hatch to provide a good alignment connection, but will add some magnets or dowels to make sure it doesn't pop off in flight too.

But I think I'll do the shaping and carving of the hatch and cowling pieces before splitting the hatch in two. So lots of balsa chips and dust coming tonight

 

[rockyboy]

Next up was working on the cockpit sides. First I glued the bottom edge and about 1/4" of the vertical part to the side of the fuselage so the cockpit pieces stood straight up. Once that was dry, I sprayed some ammonia on the cockpit sides, let it soak in for a minute, and then carefully bent them over and taped them in place until they dried (picture below). They were a little bit long and bumped into each other, but that's fine at this stage. Also bent up the tail wheel and soldered on the wheel retainers - going to try and remember to install this before the rudder hinges this time!

Once they dried in their new curves shape, a little quick work with an emery board made them fit together smoothly, and the rest of the piece was glued in permanently. Little clamp is making sure the pieces stay lined up at the butt joint

Next was attaching the bottom decking and cowling pieces. I swapped out all the 1/4" thick pieces for 1/8 or 3/32 which cut the weight in half - no need for all that extra bulk when I'm not planning to sand it round.

Next was the sanding - luckily there was a nice breeze outside...

Then it was time to reduce the weight of the hatches a bit...

And then separating the hatches and putting a couple pins to hold the battery hatch to the more solidly mounted cabane/servo hatch. I was concerned about the strength of the battery hatch where the pins go through the thin end, so I put a coat of epoxy on the inside of that part and soaked the rest of the end grain and holes on the hatches with Superphatic glue.

Going to need to think about some air venting too so the pressure doesn't try and push the battery hatch off in flight. Maybe a gap behind the bottom wing - that would let airflow go over the motor, through the ESC compartment, and then exit behind the servos and receiver. There is already a nice gap above the firewall below the inside of the hatch to encourage that flow... just need to make sure the gap around the prop shaft is large enough.

Time to move onto the tail section - first the horizontal stabilizer...

The vertical stabilizer gets an end cap installed - things get stronger with the cross grain pieces glued together. Putting the elevator halves onto the connecting dowel too...

Then the vertical gets mounted, carefully held at 90 degrees with some jigs. (FREDe 300 getting some wing mount repairs on the side)

And then the fuselage stringers get installed. I only glued and pinned these to the formers - I'll sand the edges where they meet the stabilizer for a better fit before gluing that part down.

And I started wiring up the electronic parts. I already selected and test fit everything before gluing the firewall in, but none of the connectors were soldered up yet. I didn't have any standard 25 amp ESC's handy, but I do have several small and powerful 25 amp multi-rotor ESC's. They don't have a BEC though, so I soldered in a little 2 amp external BEC to the circuit. These can be connected with only 3 wires instead of 4, which saves on weight and wire tangle. I think the picture below does a good job of explaining the wiring.

Next will be finishing the stringers, building the outer cabanes, getting the servos and control rods installed, and connecting the ACE foam wing halves. Also getting close to a weight check time too - that will tell me if I need to start cutting lightening holes in the sides of things!

[Edit] Looking back over this, I think I need to put an end cap across the back of the horizontal stabilizer too! That will be a little trickier now that it's on the plane, but much better to make that correction now rather than after the stabilizer curves up like a potato chip when the covering goes on!

And speaking of covering, I'm starting to have that mental crisis now too. I picked out a white / red / gold set of rolls from the pile that I liked the look of, but then when reading over the ACE foam wing instructions noted that it specifically says to use low temperature covering - not standard Monokote. So the covering scheme is back up in the air while I pull down that pile of rolls. I'm still comfortable with using a heavier duty covering on the fuselage, but not the wings.

 

[OliverW]

Next up was working on the cockpit sides. First I glued the bottom edge and about 1/4" of the vertical part to the side of the fuselage so the cockpit pieces stood straight up. Once that was dry, I sprayed some ammonia on the cockpit sides, let it soak in for a minute, and then carefully bent them over and taped them in place until they dried (picture below). They were a little bit long and bumped into each other, but that's fine at this stage. Also bent up the tail wheel and soldered on the wheel retainers - going to try and remember to install this before the rudder hinges this time!

View attachment 142005

Once they dried in their new curves shape, a little quick work with an emery board made them fit together smoothly, and the rest of the piece was glued in permanently. Little clamp is making sure the pieces stay lined up at the butt joint

View attachment 142007

Next was attaching the bottom decking and cowling pieces. I swapped out all the 1/4" thick pieces for 1/8 or 3/32 which cut the weight in half - no need for all that extra bulk when I'm not planning to sand it round.
View attachment 142012

Next was the sanding - luckily there was a nice breeze outside...

View attachment 142015

Then it was time to reduce the weight of the hatches a bit...

View attachment 142014

And then separating the hatches and putting a couple pins to hold the battery hatch to the more solidly mounted cabane/servo hatch. I was concerned about the strength of the battery hatch where the pins go through the thin end, so I put a coat of epoxy on the inside of that part and soaked the rest of the end grain and holes on the hatches with Superphatic glue.

Going to need to think about some air venting too so the pressure doesn't try and push the battery hatch off in flight. Maybe a gap behind the bottom wing - that would let airflow go over the motor, through the ESC compartment, and then exit behind the servos and receiver. There is already a nice gap above the firewall below the inside of the hatch to encourage that flow... just need to make sure the gap around the prop shaft is large enough.

View attachment 142009

Time to move onto the tail section - first the horizontal stabilizer...

View attachment 142008

The vertical stabilizer gets an end cap installed - things get stronger with the cross grain pieces glued together. Putting the elevator halves onto the connecting dowel too...

View attachment 142011

Then the vertical gets mounted, carefully held at 90 degrees with some jigs. (FREDe 300 getting some wing mount repairs on the side)

View attachment 142010

And then the fuselage stringers get installed. I only glued and pinned these to the formers - I'll sand the edges where they meet the stabilizer for a better fit before gluing that part down.
View attachment 142006

And I started wiring up the electronic parts. I already selected and test fit everything before gluing the firewall in, but none of the connectors were soldered up yet. I didn't have any standard 25 amp ESC's handy, but I do have several small and powerful 25 amp multi-rotor ESC's. They don't have a BEC though, so I soldered in a little 2 amp external BEC to the circuit. These can be connected with only 3 wires instead of 4, which saves on weight and wire tangle. I think the picture below does a good job of explaining the wiring.

View attachment 142013

Next will be finishing the stringers, building the outer cabanes, getting the servos and control rods installed, and connecting the ACE foam wing halves.

Also, looking back over this, I think I need to put an end cap across the back of the horizontal stabilizer too! That will be a little trickier now that it's on the plane, but much better to make that correction now rather than after the stabilizer curves up like a potato chip when the covering goes on!

And speaking of covering, I'm starting to have that mental crisis now too. I picked out a white / red / gold set of rolls from the pile that I liked the look of, but then when reading over the ACE foam wing instructions noted that it specifically says to use low temperature covering - not standard Monokote. So the covering scheme is back up in the air while I pull down that pile of rolls. I'm still comfortable with using a heavier duty covering on the fuselage, but not the wings.

Awesome! And how do you like the FredE? I have been eyeing that kit for a year or 2

 

[rockyboy]

Awesome! And how do you like the FredE? I have been eyeing that kit for a year or 2

I wanted to like it a lot more than I did, but I think a few changes will help it a lot. First, I flew the thing with a 3s battery - and that much thrust was overkill. Even half throttle in the air was too much! Also, it's a weird bird aerodynamically. It's very short coupled so it's pitch sensitive, especially if there is a lot of thrust or wind gusts involved. The wing is short too, so it's roll sensitive - and the wing on this one I bought has no dihedral - so if it rolls over on it's side, it wants to do a spiral dive. The only stabilizing feature of the whole design is having the weight of the fuselage and battery being so far below the wing - that wants to keep up and down properly sorted out.

She looks so goofy and fun just floating across the sky it put a smile on everyone's face - but with the 3s battery I found takeoffs to be scary as heck, and on the second flight she only made it up about 10 feet before my heavy throttle thumb (to overcome grass resistance) screwed things up and flipped her into the ground, breaking off the wing. It was a simple epoxy repair, and next time I'm bringing 2s batteries!

 

[rockyboy]

Little bit more progress last night.

Added the strengthening spar to the horizontal stabilizer (really would have been much easier before I attached it to the fuselage).

And started on the wings - sliced off a little bit of the foam and epoxied on the balsa trailing edges.

 

[rockyboy]

Continued work on the wings - pulled cast-off door trim pieces with 45 degree angles to use as a guide to cut the wing tips to proper length.

With a little sanding, they came out well matched!

Then it was time to sand the bevel at the root to set the dihedral using a sanding block I glued together following the ACE instructions

And once everything lined up in another jig to keep things steady, a little epoxy will keep them together.

Now checking lateral balance on the wings - the instructions talk about foam density being enough to throw the balance off, and I found I did need to stick a couple grams of control rod into the wing tip to get them to balance right.

Next I lined up and epoxied in the control rod guides so I can close up the fuselage.

 

[PoorManRC]

DANG!!!! You is one Busy Man!!! 😲😉
I feel bad now for bothering you. 😞

Those Foam Wings aren't from 1972, ARE they?? I'm sure it's more common than I know of, but that hybrid Balsa/Foam combination seems very unique to me!

From what I've read here, flying her seems way above my pay grade! 😜 Looks really interesting, and I look forward to seeing this go together - and Fly. 👍👍

 

[TooJung2Die]

And once everything lined up in another jig to keep things steady, a little epoxy will keep them together.

It looks like the wing halves are butted and glued without a joiner. Did I miss something? I like the balsa trailing edges. Was that part of the kit or your idea?

 

[rockyboy]

Thanks guys! Yes this kit is an oldie, and I think this balsa trailing edge was an idea older than that! It works great for adding enough strength to handle rubber bands and make a nice clean covering edge - don't think it does much else though. No joiner or spar so I won't be too energetic with my dives on this one. Might add a strip of carbon tow for extra strength though....

 

[PoorManRC]

I think I would definitely add a Carbon Spar of some sort. If she gets out of shape on you, you need the confidence pull out of it!

Of course I'm not telling you anything you don't already know. 😉

 

[rockyboy]

Yeah, the need for a little extra strength kept bugging me last night, so I added a strip of carbon tow with epoxy on the bottom of both wings.

That did a whole lot for extra strength - once it dried I can put a whole lot of pressure in the center and the wing just bends - no breaks. I didn't put a scale to it, but I'm betting it will hold over 20 pounds easy. Then it was time for a little filler on the roughest spots - once that dries it'll be time for covering.

Last night I also glued on the bottom sheeting on the fuselage

And then today I trimmed that down and cut off the control rod tube smoothly.

And then it was time to epoxy the tail wheel in place with a bit of fiberglass that came in the kit. The fiberglass was a bit old and stiff and wanted to pop up so I put a piece of plastic baggie and a clamp on it to sit for a while.

 

[PoorManRC]

Carbon Fibre TAPE??? Now I know I'm OLD! 😜 Never heard of it before. Is that for tensile strength?

 

[rockyboy]

Carbon Fibre TAPE??? Now I know I'm OLD! 😜 Never heard of it before. Is that for tensile strength?

Exactly! Amazing tensile strength - but worthless for compression so apply with appropriate planning.