kregan

I hate to start multiple threads about the same project but the first one got a little messy.

Good news... After placing all the components into the plane it looks like the batteries will need
to be right up against the front of the wing tube and not pushed all the way forward. I think removing
the original composite rudder in my original build and using push pull setup on the rudder helped a
lot in this regard.

Below are the before and predicted after weights with the Nano tech batteries at 630 grams.


Glow setup:
Brio ready to fly dry = 165oz. Or 10.3 pounds.
Brio ready to fly wet = 187oz. or 11.68 pounds.

Subtract:
fuel and tank – 22oz.
OS 140rx – 30oz.
header, pipe, servo, = 6oz.

Total = 58oz.
58oz – 187oz = 129oz or 8.06 pounds

This includes a fromeco 2400 2 cell rx pack, regulator
and a Hyde mount and nose ring. I don't know what the
difference will be between a Hyde mount and an electric
mount?

-

Electric components:

5s 5000 mah = 22.22 ounces (630 grams) X 2 for a 10s setup = 44.44 ounces (1260 grams)
Motor Hacker A60 v2 = 21 ounces.
speed controller = 3 ounces ???
Motor stand offs - 2 ounces

129 + 44.44 + 21 + 2 + 3 = 177.22 ounces or 12.46 pounds.

kregan

I think it was Anthony that said he cut a new firewall for his conversion.

I thought about cutting out the original firewall leaving appox. .75" around the perimeter as a former. Then add a
new firewall further forward. At 2 ounces the stand off's just seemed less intrusive and would be about the same
weight once I added up glue and materials.

One detail I did not share was on the last flight of the glow engine I burned a plug and the plane was dead stick... Worst
possible place, low, slow, and already near the end of the runway into the wind. I tried to turn it in for a landing but had
to "land" in the tall grass. It ripped the landing gear out and did a little damage to the bottom of the fuse. I decided to
completely remove the landing gear components and will reinstall them a little lower in the fuse. This may gain me
about a 1/2" clearance for a larger prop.

How about some old school retracts? LOL I bet the Brio would look nice in the air without landing gear!

john agnew

Kelly

Looks like a neat motor install. I think you need to check your arithmetic, your 2x lipos at 1260 grams convert to (1260 divide by 28 grams / ounce = 45ounces and not 22.22) so your final weight will be over 12lbs.

Regards

John

kregan

Darn your right, I typed in 22.22 for two packs..... it is 22.22 for each pack!

I guess it will be quite heavy at 12.6 pounds. At least with the batteries close to
the wing tube I won't notice the change in CG as much when the packs run down!

kregan

That 12.5 pound number was really bothering me so I put the plane together
and weighed it. It weighd in at 5100 grams without speed controller installed
but a very heavy 140 gram prop on the nose.

That makes me feel better!

Ryan Smith

My Feedback: (25)

Kelly, did you CNC those standoffs? I would be interested to see how stiff your motor is once mounted. I am kind of curious to do something similar to one of my airplanes.

tommy s

My Feedback: (55)

I'm sure this has been asked before but at the Nat's are electrics weighed with or without the batteries ?

tommy s

Ryan Smith

My Feedback: (25)

With batteries.

tommy s

My Feedback: (55)

Thanks

tommy s

MTK

Kregan, The 4 stand offs get you in the air fast except......

2 ounces for stand offs is heavy plus at least 2 ounces for firewall, as I see it in the photos.

If you need to take more weight out of the crate Isuggest thatyoucut the whole current firewall out of it and grind the epoxy off to the fuse wall. Your new "firewall" doesn't need to be a typical firewall but either a three of four armed truss. The weight of the thing, assuming you will laminate the typical cross grained balsa/carbon stock, shouldn't weigh more than 15 grams and will be plenty strong for a motor. Also, the Brio pipe floor was a piece of glass laminated balsa; weighed about 2 1/2 ounces.

I use cross grained balsa and carbon laminates for firewalls for my gas engines, and remove much of the center area of the firewall. Looking back at my notes myplanes which use OS 33 or the current one,DLE55 up front, have a firewall built this way which weighed about 38 grams. Point is, the stuff is extremely strong.....

kregan

Ryan, I cut the stand off's on a manual lathe. The lower stand off's are a bit shorter so I have
1 degree of down thrust at the moment. Right thrust was built into the firewall.

MTK, The floor of my brio is a glass covered honecolmb material and the fiewall is cross
grained balsa with carbon fiber on both sides.

The entire plane really could use a repaint and recovering after the gear repair and now lowering
so if I am not happy with the way it flies using the stand off's I can cut out the firewall and move it
forward next winter.

J Lachowski

My Feedback: (46)

Does your final weight include still using the 2400ma fromeco battery? If so, may I suggest using a 730ma 2 cell lipo instead with voltage regulator. You will easily get 6 to 7 flights out of it. That is all you will need in an electric setup. And if you are willing to spend the money, you can save over half the prop weight going to a CF prop.

MTK

I meant to say that I saw that FW construction and is what I use also. Except I remove the centers from mine to accommodate the rear mounted carb in my gas engines. Saves weight and is still plenty strong.

I did a similar glassed balsa pipe floor in my Delta and wasn't happy with the weight of mine. I changed it to glassed foam and shaved more than 50% the weight of the glassed balsa unit. In my Delta the pipe floor is there strictly to guide airflow and doesn't serveas pipemount....

Jetdesign

My Feedback: (8)

If you are going to fly at Nats, there is some cushion to the weight limit depending on what class you fly.

Your batteries are heavy - Rhinos? They are like the heaviest I've seen, I have a pair about the same weight. I'm now flying 4500mah packs, and most brands are closer to 1000g. My Zippy 5000mah packs are closer to 1100g.

Also what Joe said about Rx pack - I run a pair of 450mah lipos or a single 800mah lipo, that's fine for a day of flying, should only be about an ounce or less.

kregan

I fly with NATS, but I won't be flying at the NATS! LOL

I actually have two 800 mAh lipo's i bought for a foamy that ended up being to heavy
so I will use those. The flight batteries are NanoTech 5s 5000. The 5s zippy compacs
were out of stock.

I did cut out the fuel tank floor and some other stuff, not a lot but we will see when I weigh
it later.

The fuse repair is finished and I set up the electrinics last weekend. The big spark
i get from my heli's is a real pain so I am going to try an anti spark setup. I made up the
plates below to hold a deans and the a push button switch. I already had holes in the
fuse from the fuel lines so went with the same layout. I didn't have a 2.5mm set screw
for the deans holder when I snapped the pictures.

Last item on the list is making a battery mount/strap system.

hook57

My Feedback: (21)

Hey guys, Didnt want to start a new thread (I did post this in the other Brio thread, even though it seemed to have gotten thrashed) so hope you all don't mind if I ask a Q here. I have a 110 size pattern plane (3 of them), one is powered with a YS1.20 currently being rebuilt and it was very well powered with that engine. Im thinking that I'm going to convert it to E power and was wondering if the following set up will work: Eflite Power 90, or Power 110 Castle HV80, or the HV85 6 cell 5000 mAh packs, or 8 cell Have only flown smaller E powered planes soother options, suggestions, or ideas greatly appreciated. Will gladly repost or move this if this is the wrong place for it. Thanks guys. Mark Hide Signatures (in reply tocrashlander)

kregan

Since battery weight can vary drasticly from one manufacture to the next I thought a tray that could slide
on rails would be nice. To prevent the tray from sliding in flight a locating tab could be added to each
tray. This tab could be ajusted and then glued in place once the balance point was determined. The
tab could also serve as a spacer to seperate the two packs for cooling.

The rods are glued to the sides of the fuse using light ply disks. The rails and rods are carbon fiber
and weigh 25 grams. The light ply tray is 15 grams before adding the locating tabs. The trays have a
spot for 3/4" wide strips of velcro at each end. Two battery straps will encompas the cells, tray, and rails.

kregan

So I had this long update typed out and it got erased with an error....

Sort recap, Plane is heavy at 11 pounds 11 oz. I test flew it and it was ok
but I decided to bring it home and strip it down and make a new firewall,
remove the pipe floor, most of it anyway and try to lighten it.

Here are some pics of all the stripped out fuse.

BTW the battery rails and tray work great, light, and rock solid!

MTK

Kelly, many Brios, maybe even most of them, were heavy to begin with. I remember buying the last couple of them and the fuses alone weighed 46 ounces (canopy and chin included). My finished model (my design wings and stabs) sports a gas engine and weighs in at 11# 5 ozs which includes 5 ounces of nose weight. The wing area is 1110 square inches and the model flies very well since wing loading is reasonable

It appears that you're not affraid to tackle the challenge so let me suggest that you build another set of wings with plus 100 squares in area. Try to get the weight the same or slightly lower if you can. It won't reduce flying weight much but will make the model feel lighter on the wing

kregan

Thank you for the fuse weight MTK

I weighed my fuse as pictured above without the firewall but with the following items installed - canopy,
chin cowl, stabs, rudder servo, elevator servo, rx with satilite, switch, the anti spark plug holder pictured
above, the stock gear mounting plate, and battery tray rails.

3 pounds 9 ouncs (57oz.).

I should weight the wings... I wonder if a built up set of wings would weigh less then the foam core?

The firewall I removed came in at 2 ounces not including all the glue I have been grinding out of this thing.
I am considering .093 carbon fiber sheeting (same as the battery tray rails) for the replacement firewall.

MTK

For the fuse to weigh that much with no FW and floor, you probably had one of the heavier fuses.

The new FW doesn't need to weigh more than 20 grams for a motor. Maybe less. You should be able to cut some of the area out.

Built up wing might weigh less with very close watch on balsa type. If you can get a set of laser cut ribs to your specs, the rest is straight forward.

Or a new larger foam core sheeted with 1/32 stock would work at least as well. I'd use 6-8 lb density. I've sheeted wings before with 1/32" stock and that works fine, You will shave an ounce plus off each panel.

I've settled on a different approach for sheeting...I start with 1/16" and taper sand to 1/32" at the tips before installing on the foam. It's a lot of dust but the weight saved is real. My sockets are always installed using half spars top and bottom, extending to the sheeting. Forms an "I" beam structure which is stronger and lighter than anything else I've seen. The half spars extend beyong the end of the socket by at least 3" eliminating the stress at the end of the socket. The spar stock is 1/8" balsa with grain running spanwise.

Consider the weight....my typical wing panel is 500 square inches. I never use plastic film on pattern models; silkspan and paint only. A panel typically weighs in at 12 1/2 ounces ready for gear. Or around 15 ounces ready to fly. Some, very few, can use plastic film and bring weight down a little more. However, most wings these days are at most 400 square inches per panel... Your choice...

Such ismy current design flying with a DLE55 up front: 530 squares each and 430 grams each RTF...Plenty strong enough for a 55cc engine...Good luck

kregan

The firewall relocation is complete and the final weight is 11 pounds 5 oz. a reduction of 6 oz.

I regret not waiting for the Zippy compac to come back in stock. That alone would have saved
another 50 or 6 oz. The NANO Tech have that heavy 10 ga wire as well.

If I toss money at the plane it could be further lightened with a carbon fiber spinner and prop but
I am just going to leave it be for a while.

If I recall the glow setup with fuel was 11 pounds 9 oz.

kregan

Weighed the wing panels...15.6 oz ready to fly.

Do you have any links that show this wing construction?

I will need to do a total refinish of the brio over the winter and would like to try the silkspan and paint
metohod instead of the film I have now on the winges. Any links to instructions and or materials
would be a great help.

MTK

Kelly,

I think I have a few snaps iof the wing building in my Derivative thread.

The silkspan and dope technique is not difficult unless you work with the light silkspan as I am doing. That material was frustrating me at first because it would stick to itself when wetand I couldn't separate it without ripping it.Uuntil I figured out thesimplest way to apply and bed it wrinkle free. Now it's a breeze and it finishes into an extremely lightweight finish if you don't go crazy on the paint.

If you are planning to use the same sheeted cores, you will not save weight but you shouldn't pick up any either.

Applying medium silkspan is no big deal....spritz it with water and apply it onto the well prepped and sealed sheeting (6 coats of dope to sheeting). Then dope (always use nitrate for bedding) it down and let it dry/shrink in place. Do both top and bottom sides to help avoid warps. Wrinkles can be worked out

Light silkspan is very tricky but you don't need anywhere near as much prep or dope to fill it. But wrinkles can not be worked out so you need to be very careful. Here's what I do:

Two coats of thinned dope to all sheeted areas. Sand after the second coat with 400 paper, dry. Thin 50:50 (and up to 75:25,75% thinner 25% dope); not that critical actually but thin it well. I use Randolphs nontautening Nitrate from Aircraft Spruce &Specialty, but Sigs works fine too. Just twice the cost, A quart is good for several wings; I also bought a gallon of thinner while at their site
Cut the paper oversize slightly and hang it from one edge so it hangs free.
Spritz it with as fine a mist of water as you can find, BUT don't soak it. Just a fine mist of water is all that's needed torelax the fibers.
Carefully place it on the sheeted surface, damp, and quickly dope down only the edges.
Let it dry and doNOT dope any more of it until dry.

The paper will dry to a drum tight appearance, like the skin on a grape. Any wrinkles it might have had will be eliminated. This method is much less sensitizing to structure regarding warps because the paper is not applied dripping wet.

Using the same 50-75% reduced nitrate, dope the paper down starting the doping in the middle. Avoid going over the same areas morethan just once
Let that dry and come back with another dope session. You can adda drop or two of black or reddope to the nitrate so you see contrast.
Very light sanding after the second coat, with 400 grit used dry

Repeat a total of 4 times. Then apply two fill coats. I use baby powder as filler. Dry sand between the filler coats.

Should be ready for primer. I use Klass Kote epoxy after allowing 3 days to fully flash. I dry sand the primer.

You can us Japanese tissue (not Esaki paper) rather than silkspan, using a similar technique. Jap tissue actually fills much faster than silkspan requiring less dope overall, and is stronger than silkspan but also at least 3X the price. Weight is similar.

Any of these finishes are extremely thin and prone to hanger rash. I tend to work on bath towels backed up with sleeping blankets

Good luck

kregan

Thank you Matt, great info.

Flight update... The plane flies great ! Not sure if the 6oz. made that much of a difference but
combined with the proper CG, a throttle curve and the proper right thrust the plane is better then
ever.

Running the 5000 MaH batteries I am replacing approx 3600 mah after 8 minutes of flight.
Batteries are hardly warm, motor is very warm but not hot, speed control is slightly warm.
LOL... very precise measurements!

It was really strange flying without the smoke trail and noise!

Question... On low throttle do you guys set a condition so the electric motor still "idles" or
do you let the motor stop? I notice at the top of an up line the prop will stop at low throttle
then start to free wheel once the ship has turned down and starts its decent. I could simply
bump the throttle trim up a bit or set a flight condition with low throttle just spinning the prop
a few hundred RPM? Not sure what the normal practice is?

Thank you all again for your help.