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Jul 08, 2019, 03:47 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
Quote:
Originally Posted by Abdullah Radwan
I had a flight today. Here is the video.

In the first try, the aircraft flew great until a gust of wind blown the aircraft into the building. I've tried to steer the aircraft left, but I lost control. No damage to the aircraft. I've run the motor several times to make sure it's clean from dust.

In the second try, I am not sure but perhaps it's a combination of a wind gust and not applying full throttle on takeoff (The motor sound is 'low' in the video, I am not sure if I applied the full throttle or not). No damage to the aircraft.

In the third try, I guess it's also the wind (Notice how the aircraft rolled rapidly into the right). This time the propeller broke. No damage to the aircraft nor the motor.

In all tries, the wind was a critical factor. It looks like I didn't respect the wind enough. I had to learn that the hard way . Based on Windy, the wind guest was about 36 km/h in the time I flew. I think this is enough to blow the aircraft. I'll try to fly early in the morning next time.

BTW, the propeller adapter worked like a charm. Much better than a prop saver. I'll always use it.

Now I have only one propeller remaining, so I have 2 options:
  • Uninstall the electronics and build a pusher aircraft with the same specs as Blu-Baby.
  • Continue with my aircraft and trying to get propellers from anywhere.
I had purchased Hobbyking Slowfly Propeller 9x5, but now they are lost.I've looked for them but I didn't find them. I'll try to look for them again soon.

Meanwhile, should I build a pusher plane? Which one is closet to Blu-Baby 33? I'll use the same electronics setup so it has to be close to Blu-Baby.
I watched your video : in all flight attempts your Blu-Baby plane seemed tail heavy , and your hand launch was too slow . If you try to fly the BB again , move the battery forward and/or add some nose weight so it has a slightly forward CG ( from where it is now ) . And throw it a little harder , making sure the wings are level and the nose is slightly up when your hand releases the plane .

If you want to build a pusher using the BB electronics , the flying weight of the pusher needs to be the same ( or less ) as the BB ..... not necessarily the dimensions . The thrust given by a motor/prop/voltage is relative to the weight of a plane , not the physical dimensions of a plane .

You could try the Super Easy in my previous posts , or you could try an EzFly . The Super Easy can be made without plans , the EzFly requires downloading & printing plans .

Here is one of my EzFlys :



Copy of EzFly with under-cambered wing (1 min 57 sec)





One thing to remember when building a pusher : if the motor is turned around facing backwards , you need to turn the prop around so the prop is facing forwards .
Last edited by balsa or carbon; Jul 08, 2019 at 03:53 PM.
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Jul 08, 2019, 09:23 PM
Registered User
Abdullah Radwan's Avatar
EzFly seems to be good. I have no problem with plans.

I have found GWS 8x3.8 propeller. I'll use it in EzFly.

I've tested the CG before each flight and it's barely on the limit (It balances near 3"). I'll use the remaining propeller in the last flight. I'll try to add more weight forward.

For now, I'll move to EzFly thread to ask questions there. Thank you so much!
Jul 08, 2019, 09:53 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
Quote:
Originally Posted by Abdullah Radwan
EzFly seems to be good. I have no problem with plans.

I have found GWS 8x3.8 propeller. I'll use it in EzFly.

I've tested the CG before each flight and it's barely on the limit (It balances near 3"). I'll use the remaining propeller in the last flight. I'll try to add more weight forward.

For now, I'll move to EzFly thread to ask questions there. Thank you so much!
The standard size EzFly ( 31"/ 78cm wingspan ) uses a 24 gram motor and lightweight battery ( 500mAh -1000mAh ) . If your electronics are significantly heavier , I recommend building a larger EzFly ..... perhaps 120% - 130% . Also , an 8x3.8 prop will be too big for the prop slot on a standard size EzFly ( without modification ) .

If you haven't already found it , here is the EzFly thread :
https://www.rcgroups.com/forums/show...-trainer-plane
The best most-up-to-date plans are "EzFly R3 Drawing" : https://www.rcgroups.com/forums/show...6&d=1334660760
Scale the plans up to 120% or 130% if your electronics are heavy .
Jul 08, 2019, 10:03 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
Quote:
Originally Posted by Abdullah Radwan

I've tested the CG before each flight and it's barely on the limit (It balances near 3"). I'll use the remaining propeller in the last flight. I'll try to add more weight forward.
In My Opinion , the recommended CG for airplanes is a starting point .... it will get you in the air . Once you are flying , evaluate the plane's tendencies ( like tail heavy flying ) .... and then make adjustments accordingly .

Making adjustments ( "tuning" the plane ) is one of the hardest things to do in RC flying ..... especially when you are a beginner . At my flying field , some RC flyers ( who have been flying for years ) still ask me to tune their planes for them .
Jul 09, 2019, 06:07 PM
looking up, down under
scruffy1's Avatar
launch needs to be with wings level with the horizin from behind, and forcefully enough to leave your hand at at least flying speed

nose slight;y up is good, because then you get some more altitude to make decisions as you burn off any excess speed; if it is going straight and climbing a little, let it fly and gain some height, it's your best asset

turning for beginners will lose some height (remember my comment on natural nose down with rudder use ?) so your first turn needs to be with sufficient space below (and around) to do so

standard axiom : always commence manoeuvres 2 crashes above the ground; translation : leave yourself height to recover from any manouevre (even turning) when you are very new to the game

in both the launches in your video you were not throwing the plane with intent - you were pretty limp

ever thrown a javelin ? or even a fast ball ? that's the sort of impetus you need

it's rare to launch a plane "too hard" - the problem with excess speed is that the nose will generally rise and you can stall if you don't compensate with a touch of down before you slow down too much and the nose (or more problematic, one wing) drops , though kfm is allegedly gentle on stall

on the other hand, insufficient airspeed at launch will have the nose drop anyway, and you will have no control authority because air flow over surfaces is what you need for that


practice running with the plane (motor off) and feel when the wing gets to the point of pulling the plane up in your grip - that's the minimum speed it should be leaving your hand, and what you need to impart with the throw

this plane is much smaller, but my launch gives you some idea (and shows how much less of a problem my site is for obstruction and soft landings)

mini-stick (1 min 41 sec)
Jul 10, 2019, 12:34 AM
Registered User
Abdullah Radwan's Avatar
Thanks for the advice. But I have a problem: When I just launch the plane, I can't remember any of those! It feels like I am going to another world
That's real. I forget everything after launch. I remember all of these after crashing.

I was limp due to the above reason, and being too anxious. I didn't want to crash the plane. But it looks like that anxiety is what making problems.

Also, I thought full throttle should be enough to climb with low speed. Should I try a flight with the last propeller? This time I'll try to remember the advice and throw at max speed. Hope that will work.
Jul 29, 2019, 07:05 PM
Registered User

New BB 42


Hi all,

I'm building a new BB 42 model. To build up the 2" monoblock. I sandwiched 1/8" balsa between 1/2" foam from the packing of a buffet cart recently purchased. So almost 2". However I'm going to cut a bit off the nose since the 1000kv motor shaft isn't quite long enough (see photo). Also I made a channel for the motor to controller wires. Sides are just taped on to mock things up.
I'm considering leaving the paper in one side of the $T foam sides to provide some contrast. Once I get more of the electronics defined I'll see where the approx CG will be.
I'm going to make the horizontal stab removable for easier transport. I don't think I can describe my idea so ... More details on to follow.
I'm planning on using a SS tube and CF rod spars for the wings rather than the plywood. Maybe even make the wing halves separate again for easier transport.
The reason I'm considering transport so much is that the nearest AMA club is about 45 mi away.

Cheers,
Jim

Edit: Abdullah you provide a good reminder that model planes show up much better against a cloudy sky.

Edit 2: Reminds me of the movie "The Aviator" about Howard Hughes. He found that making an airplane dogfight movie in clear sky provided no reference for the airplane speed. So he also started filming on cloudy days.
Last edited by jgreetham; Jul 29, 2019 at 09:32 PM.
Aug 08, 2019, 10:08 AM
Registered User
And... My completed BB 42". I have found a couple clubs within about 45 min of me so I plan on taking it when I go to visit. Maybe I can post a flight video.

Cheers,
Jim
Sep 15, 2019, 09:33 PM
Build, crash...repeat
AleRRon's Avatar
Jgreetham
Nice build. For future builds, if you find the motor is short and wonít clear the nose, you can leave the airplane alone and just use nylon spacers and longer screws to secure it to the firewall. Iím sure your model will fly fine the way you did it though, as long as the CG is where itís supposed to be.


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