tubig

New Project: Brian Taylor's 68" wingspan Bf109E-3 which will be done in Helmut Wick's Bf109E-4 colors of November 1940.

Engine: RCV90SP turning a three-bladed prop.

Retracts: Unitracts mechanical units originally designed for this plan.

laser cut parts and accessories from Bob Holman.

tubig

here is a shot of the RCV 90SP and mechanical retracts from Unitracts.

tubig

horizontal stab framed up. this is my first build on my new glass work top. so far, first class.
the second photo shows the two halves of the horizontal stab sheeted separately and then joined.
and finally, the tips added.

tubig

elevator halves roughed out and then sanded to fit. it was suggested to me to use separate servos for each elevator half so used aileron strip linkage on each half.

Katchmarek

My Feedback: (29)

Lookin good! I'll be following your build, this is a great subject.
Rob / katchmarek

tubig

thanks rob. i know you're a big luftwaffe fan as am i.

tubig

construction on the fuse beginning with the front end. i had to make a couple of new firewall support pieces since the RCV required the firewall to be located about 1/2" more forward. here is construction of the firewall box and mid-fuselage/wing cradle balsa slabs.
i had to lower the 1/8" ply fuel tank floor about 1/2" due to the metal back plate used to mount the engine. i will wait to permanently mount the firewall until i get the muffler extension i want to use to make sure everything fits as planned.

tubig

the rest of the fuselage composed of crutch, cross pieces and half formers.

Foxbat711

My Feedback: (29)

I guess your building the 68" Taylor Bf-109 Emil from Holman?

tubig

yeah, that's the one.

tubig

the fuselage planked with 1/4" strips and rough sanded. will wait until all rear fuse sheeting is on to fully sand.

tubig

here the top formers on the rear fuselage. and the rear saddle support pieces. these pieces were a little tricky to put in because they really don't "lock" into anything as it looks on the plan. right now they are still just tacked because i need to complete the tailwheel support bracket and glue that in between these pieces before permanently gluing everything in.

tubig

tailwheel construction. i'm using 3/32" piano wire with two pieces of brass tubing as shims/axles. i soldered on a washer to the largest of the brass axles which is placed on the "inside" next to the upward turn in the piano wire preventing the tire from rubbing on the piano wire. on the outside of the axle, my plan is to drill a hole in the brass tubing and insert a cotter pin which holds the tire on but still allows for changes if necessary. i'm also going to grind down the washer to just large enough to hold the tire. still looking for a suitable cotter pin. i'm following BT's plans for the tailwheel bracket.

tubig

spent most of a day setting up the pull-pull rudder linkage. this was very fiddly as there's not much room to work. i used the hardware parts of a 90 deg. bellcrank pkg. but making the arms from g-10. that g-10 is tuff stuff. i've already ruined one jigsaw blade just cutting two blanks. the linkage is temporarily tacked into place and won't be permanently attached until after the fin/rudder are in place in case i need to make some adjustments. both sides of the linkage bracket will have 1/4" sq. balsa gussets when it's permanently mounted.

Foxbat711

My Feedback: (29)

Nicely Done.... Expected weight of the model? How are the plans? Any building instructions supplied?

tubig

BT notes on the plan that the prototype weighed in at 10 1/2 lbs and balanced on the cg w/o use of nose weight. the plans are good. even though this is my first experience with BT plans, i've heard that all of his plans are good. no instructions to speak of. just notes here and there on the plans. as you can see from the photos so far, the plans build a simple but strong model. i'm using mostly contest grade balsa on this so i think a 10 lb. model may be doable. the one thing i've noticed is that the laser cut parts from Holman don't match up exactly with the plans so i'm not building over the plans. i'm just using them as a guide and dry fitting parts before gluing in.

SCALECRAFT

My Feedback: (13)

Tubig

I too am planning on building the my BT 109E, but have chosen the RCV Sp120 for it. Why?? I think the engines are good design, but a bit underpowered even with the 2:1 gear down. Still i liked them enough to own the 120.

Note that on RCV's web site thier SP120 max wieght for a plane is 11lbs. The 90 may not be the ideal engine for the BT 109E. It may be better for the BT 109F 61" span, a project also in the rafters somewhere.

See thier web site for inpotant specs. Note that according to RCV, normal operating temp for this engine is between 315F- 356F. Seems, hot but thats what the email said.

Steve

tubig

steve, that sounds a little depressing to me as i've already bought the engine. well, since i've got it i might as well try it. if it happens that she needs more power then i guess i'll put something bigger in. thanks for the heads up.

Idigbo

Tubig, you need some re-assurance I reckon!

I had a 90 sp in a thunderbolt, 71 span, about 10 lb I think, and it perfomed very well, wouldn't do endless vertical rolls though

The Bt design is quite lightly loaded for a warbird, compared to some, so if you want scale type flying, it'll be fine. How are you planning the cooling?

I built a 109E-4 a while back, with a Laser 150 V, and the cooling air entered from the chin, ducted round, and the smaller intake behind the spinner. Cooling air escaped through the rear of the oil cooler radiator under the chin, and also out of ten of the twelve exhausts, the other two, one each side was the Laser exhaust. This system worked really well, with no cheat holes. I would have thought the RCV could be cooled in a similar way, although air must travel through the fins, not over them which is what happens with no ducting ( apologies for teaching granny to suck eggs if I have!) Here is a couple of pics of my Me109E-4, in Adolf Gallands colours, span is 74" btw.

Watching this with interest!

Ian.

tubig

thanks ian. you're right about the how lightly this builds. i'm wrapping up a TF spit and these two don't even compare, the TF being a refrigerator compared to the BT design.

for the cooling, here's a shot of my plan to add ply ducting from the top and bottom inlets and exhausting the air through the rear as i believe you did from your description (sorry that it's hard to see, i did it in pencil). i had thought of the using the exhaust stacks as well but still undecided on that. my plan is to resin cast the stacks and not sure if i want to drill holes through them.

your model is fantastic! i would swear that the second pic is of the real plane. very well done! you've set the bar for me on this one.

tubig

work on the rudder/tailwheel and elevator controls. i ran into two small problems. first, you can see from the photo below that the precut parts for the horizontal stab come up well short in thickness. i added two 1/4" pieces on each side to make up for this and will be sanded to shape later. secondly, because i decided on using one elevator servo for each elevator half i needed to cut out most of the solid balsa to make room for the horns. instead of leaving a very thin, flimsy balsa piece to get broken multiple times i cut out a section and replaced it with 1/64" ply as shown.

tubig

got the bellcranks for the control rods made. i'm going with BT's plan using 180 deg. bellcranks which connect the control surfaces to the servo; however, i'm putting the rudder and elevator servos closer to the bellcranks than the plans show (i'm putting them just on the other side of the bellcrank former). i made these the same way as the pull-pull bellcrank for the rudder using hardware from a 90 deg. bellcrank and using g-10 with washers added for spacing.

tubig

closed up the back end with 3/32" sheeting. after watching dave platt's videos i thought i would give his method of joining sheets together a try by sanding a little prior to gluing to get some balsa dust in the joint and ca'ing. i was a little nervous about sanding the hard ca but using 80 grit paper did a pretty good job. the second pic shows the cap strip added.

tubig

the forward fuselage formers are in place and sheeted. i had a small problem with a couple of the laser cut formers being a little too narrow at the bottom of the former. looking closely you'll see where i had to add some balsa to make them fatter so the sheeting will lie in a straight line.

i tried a new method of applying sheeting this time that i've heard about . it uses an iron to polymerize aliphatic glue after it is gelled but before dry. i did it by applying aliphatic to the formers and then laying the sheeting on top and pressing down to transfer a "line" of glue to the sheeting. i removed the sheeting, re-spread a thin line of glue on the formers (to cover any areas where it was removed by the sheeting) and over the "lined" area on the sheeting. i let these sit for about 20-30 minutes and then put the sheeting back on and ironed it down. it worked very slick. i had all the time in the world to position the sheet before gluing and once the heat was applied there was an instant bond. plus, by pressing down with the iron there was little chance of the sheeting pulling up as with weights or pins.

wulf190

My Feedback: (19)

Tubig, I cut out all of the wing ribs, then Skyshark came out with their Emil and I fell into one on ebay, so my ribs just sit now. I love the way the thing goes together though. Lot's of balsa and little heavy plywood. I saw it building really light due to the way the fuse is built. It looks like it will be a good flyer. Keep up the fine work. I'm enjoying watching the plane come together.