I thought I’d put the wings on the QB™ for a little inspiration to finish it up… beautiful, and the fit and finish is perfect, everything sliding in place like butter. I think this plane ROCKS!
I got a smile on my face, once again, while seeing what was included with this QB series plane. Aeroworks not only cut the brass tubes to the length I like, but they also included fuel barbs to solder onto the brass tubes. Very nice… otherwise I always solder on DUBRO barbs… but so nice to have all this stuff included and cut to length:
I finally got back on this thing… went to mount the engine… Aeroworks includes templates for DA and 3W (same hole pattern), but none for the BME. But, it’s easy enough to use one of the provide templates to do the job. Just measure and mark the BME pattern on it, using the factory cross hairs for guides:
Next I drilled the four holes:
Then taped the template onto the motorbox:
And, ran the 13/64″ bit through the firewall:
The BME is a short engine so the provided engine standoffs would not get me much, if any, clearance prop-to-cowl. I should have already ordered something the right length, but haven’t. I did have some 2-1/2″ spacers laying around from something (either a DA-50 or from Gus, I can’t remember). I used those and some 4″ 10-32 socket allen heads machine bolts from www.microfasteners.com . The BME is setup for 10-32s, btw:
This has me hanging out about 1-1/4″ at the tightest clearance location. There is talk about the benefits of having your motor stick out there aways’ on these big round cowl Yaks, etc. But, I also don’t want to increase the nose moment. So, I’m thinking to cut these down or get Gus to make me a shorter length, which would mean no maiden this week:
BME gives you two hole patterns for the prop. They are the same dimensions as a DA-150/3W-150 and a 3W-106/DA-100. The prop in the picture above was drilled for a 3W-150, as was the spinner shown above, and they bolted right onto this lil’ engine. So, it appears, anything drilled for any of the above mentioned motors will bolt onto this BME… but with 10/32 bolts and not 5mm bolts. Kinda cool because the 30-10 Menz prop I have is already drilled for a 3W-150… but if this engine can swing it after break-in… then I can use this one instead of having to buy a new one to drill for a standard 100cc size hole pattern:
The BME-115 comes with an Addendum sheet that says:
“The new six bolt prop drive from BME features a 10mm centering boss and a 8mm x 1.25 center bolt that MUST be utilized and six 10×32 x 1.75 socket cap bolts. A unique feature of the prop drive is that it incorporates both popular bolt patterns. When installing propeller user must make sure to alternate between outer bolts and center bolt to insure all are tight. They should also be periodically checked for tightness especially so when using wooden propellers. Due to the design of the crankshaft the center bolt threads should be sealed with automotive silicon to prevent leakage from the crankcase. It is not sealed from the factory due to different prop and spinner widths available.
The high performance characteristics of the BME 115 require an oil ratio of 32:1 or 4 ounces per gallon. We highly recommend Pennzoil Air Cooled Two Cycle Oil for break-in and everday use. It is imperative that users duct/baffle cowls for proper airflow and cooling.”
Well… “automotive silicon”… there’s lots of that around. But, the stuff I normally use from Permatex… RTV sealant in black or copper colors… says right on it that it is not recommended for use around gasoline. So, I picked up two gas resistant sealants… trying to decide which one to use. One looks cool, says all the right things:
MotoSeal® 1 Ultimate Gasket Maker Grey
But, the other one gets hard and is for threaded applications:
Permatex® Form-A-Gasket® No. 1 Sealant
What to do, what to do. lol
Anyway, the ignition finally showed up so the BME gets a new photoshoot:
Big Bob Knudsen told me the 2″ standoffs yield too much vibration… maybe I should just go with my old method and build a ply spacer. <shrug> 5 years ago, first gas engine mount I ever made:
I decided to go retro-joe meets modern day QB™. lol I made a wood spacer =and= used the Aeroworks aluminum standoffs. Not only that, but everything is drilled to such tight tolerances that this thing is very solid and rigid. It’s a little weird looking, but I like it. lol
First I cut some ply squares and Zpoxied them together:
Then, I clamped ‘em:
Then I used a hole saw to lighten ‘em up:
Then, I used a drill press to drill the bolt holes:
I sanding the block down with a belt sander (this is actual very easy with a spindle sander), but here’s how I pencil’d out my outline:
After that I gathered up all the necessary fixen’s:
And, here it is:
BTW, more quality features:
Aeroworks shows 7-3/4″ from the firewall to the prop hub, I made it 7-5/8″ just because that is what I wanted to try. This leaves 7/8″ clearance at the tightest point between the cowl and the prop:
Oh, I did drop back and take out the philips head bolts on the wheel collars. I replaced them with these socket heads from MF:
They could even be a tad shorter, next time I’ll try these: SCM3005 20 M3 x .5 x 5mm $ 1.80
I did a dremel chamfer to round out a couple of DUBRO ball joints to use for the pull/pull as “tensioners”:
Just finished up the pull/pull rudder system. Took about 15 minutes. Aeroworks takes =all= of the guess work (calcs) out of this assembly. I like my pull/pull cables to be as perfect as possible, with the non-pulling cable neither getting loose nor tight. What was fun here was having built a QB™ before. On that first one I explored all the possibilities and calc’d them all out. Then tried the stock method planning on modifying it. Turns out it was perfect, as per the manual. =So= on this one I just slapped a 3″ full servo arm on the rudder servo, pulled the included pull/pull cable through the factory installed exit tubes; crimbed the cable on the connectors; bolted it all down; and I was done… perfect geometry, the non-pulling cable does not go slack nor tighten up. Very, very easy to do a great job here:
Say hello to my little friends:
They are relatively inexpensive Cobalt bits from Home Depot:
Me and Dunny have been having a hard time finding anything we need at the Home Depots, et al, up here in these parts. But, HD came though for me with these today. I’ve never been able to drill these hardened steel carb arms before… so the only way I was really happy with them was if I went and had the extensions I made for them welded on. But, no more, these bits drilled the hardened steel just like a tick into a country hog. I will no longer dread this part of the assembly process (of course EVO puts a nice 3 hole aluminum arm on their carbs making it a moot point if you have one of those engines):
I have a bunch of these old Nelson servo arms and always seem to need one for this or that, worked out great here, too:
I used 2-56 stainless steel bolts from www.microfasteners.com because I didn’t think there was enough meat (meat, hog, get it? lol) there for 4-40:
I didn’t have any 2-56 washers so I used some old 2-56 basic nuts I had laying around (note to self, order some 2-56 stainless steel washers). And, I used www.microfasteners.com 2-56 SS nylon locking nuts on the back side:
If you want your throttle response to be linear and have lots of resolution you just can’t set it up any ol’ way:
The Fromeco charger below is so cool I had to post a pic of it in action.
I have the 1200mah Lith-poly charging at 1amp, the 2600mah Lith-ion “grunt” charging at 1.5amps, the 2150mah Lith-poly charging at 2amps, and the 5200mah Lith-ion “grunt” packs charging at 3amps each. The charger auto-sensed the cells (i.e, 2S or 3S) and asked me what amperage I wanted to charge them at. Too cool:
Well, after I finished talking to my friend Khalid Al Sabah from Kuwait about model planes… I got started on the fuel tank. Aeroworks includes a fine tank, but I’m used to using DUBRO tanks and had one laying around… I’m comfortable with them, they’ve never let me down, so anyway, I used the DUBRO tank (32oz):
I always set my tanks up with 3 lines through the stopper and also use two clunks; the heavy one that is included with the 32oz DUBRO tank for the carb line, and a “standard” size DUBRO clunk for the fuel/defuel line:
I used the DUBRO tank and gas stopper (the brown one), but used the 1/8″ tubing from the Aeroworks tank. It is already cut to the lengths I like, so that saved a step. I also used the Aeroworks solder on barbs to keep the fuel line from ever coming off in flight (I usually use the DUBRO barbs, but this is the first ARF I’ve ever seen that has barbs included). Here is the the 3-line tank setup I always use (it has never failed me):
NOTE: You must make sure any fuel line you use is DUBRO or DUBRO quality or it can stiffen up and lead to a flame out.
My friend used some line from an Aeroworks ARF that did stiffen up on him. Totally rigid. He flamed out while doing a slow inverted pass, it was a lucky save. The upper line (the carb line) in the pic below is completely rigid, even when soaked for an hour in gasoline! You can also see that it has shrunk. My friend’s first clue was that his engine was too lean to start even though last time he flew it (6 months back) it ran perfectly. We always get a warning, but oftentimes don’t notice it. He turned the needles way out and flew. After he burned off a little fuel and went inverted he flamed out… no gas… even though he had 7/8 of a tank! Just make sure you have the good line:
Aeroworks included a ton of foam that can be used here just fine:
But, I went with the blue NASA foam because, I don’t know, old habits die hard:
Oh, my Pennzoil Air Cooled 2-stroke oil showed up. Even though I wanted to just use Lawnboy for break-in; I acquiesced and used the BME recommended Pennzoil Air Cooled 2-stroke oil. Fine, fine, I’ll check it out… maybe it is better than lawnboy, who knows:
Went to mounting the radio gear on this thing. Going with a www.smart-fly.com Power Expander “Sport.” Why? Because I want more current to my servos than a standard R/C connector can provide (if I ran the battery power direct to the RX without a power distribution system, then all that 16gage wire and Dean’s Ultra connectors would then have to pass through a little 1.9amp standard R/C connector into the RX, to provide all the power to my servos, which by the way, can draw 4amps each). Also, Fromeco Regs all around:
Before I got started mounting things I adjusted the regs to 6.21 volts each (that was the max I could get them to) with a switch Jimmy made up for me. Fromeco sells one, too… or you can just use a screw driver, etc:
I decided to do the mounting with blind nuts, 4-40 bolts, nylon lock nuts, tygon fuel line spacers, and stuff like that:
I always want to just grab the standard drill when doing this stuff, but if you want the holes to be straight while drilling in tight spots inside the plane you gotta break out the right angle attachment for the dremel:
Here’s the Smart-Fly PowerExpander Sport mounted up:
I always glue in the blind nuts with ZAP thin CA. It penetrates and holds them in place pretty well. I make sure not to have a bolt in the blind nut when I glue the blind nut in place. Because if you have a bolt in there and that ZAP thin gets ahold to’ it’… the whole mess will be monolithic, baby:
Here’s the Fromeco regulators mounted up:
Wanted to get the rest of the radio gear mounted but got tired. lol Here is the layout, though. I figure with this light engine I’ll want the gear all up front like this. If this works out I won’t have to install the center tray ‘tal:
