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HelicopterMain Discussion › How Fas Do a 450 Go?
08-01-2013 01:14 PM  4 years agoPost 21
icanfly

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ontario

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can not spell for $hit
it's intentional on occasion.

I was at ytb looking at Henseliet speed runs (117).

A Trex 700 with a 4hp motor sounds like it could be faster than a 450 but it's maybe 8-9 lbs. If that's 1/2hp per lb then it's half as fast as a 1hp to 1lb rig. That may or may not be true depending on the amount of torque the motor produces. When a heli is in full collective pitch the blades are corkscrewing the air like a prop. What do you favor, torque? or hp which translates to rpm?

One area of loss would be in that the heli is using collective and pitch at full tilt and there's loss on the pitch aspect. Then you have a tail drive system eating up 20 percent of the main potential.

What's a boy to do?

(forget the canuk thing)

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08-01-2013 08:39 PM  4 years agoPost 22
Luvmyhelis

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Spokane, Washington. USA

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We have gps on a pretty much stock drive train porky fpv fbl 450 with a guy in our club. He is running 360s on it though. Pretty much stays just above 60 and hits just under 80 in dives. It bumped up 10mph with a new Yep esc as his Scorp esc wasn't up to the task two weeks ago. Next week he will be running 6s in it with a Scorp 2221-2010 and a 13T. I expect it will be faster. This is a fairly heavy 450 as it is loaded with larger capacity packs for distance flying and all the fpv gear.

So yeah, this is verified with Gps and he has vids with the read outs on the screen. Also a couple gnarly crashes when he lost his link. I hear it took hours to find it.

Old cranky heli builder

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08-10-2013 12:27 PM  4 years agoPost 23
mystar60

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Clifton, NJ

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08-10-2013 01:37 PM  4 years agoPost 24
icanfly

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ontario

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ok! wow!, holy s-h-?-T!!! Now we talkin.

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08-10-2013 03:36 PM  4 years agoPost 25
kingmeow

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The Garden State, US

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Didn't someone did a speed run with a Blade 300x and clocked it at 100 MPH? It was subsequently disqualified due to not meeting the minimum size. Check the IRCHA 2013 speed run thread.

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08-10-2013 03:54 PM  4 years agoPost 26
icanfly

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ontario

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minimum size? that's a riot.

I guess the mean angle of attack due to the mains providing lift and forward propulsion is on average 30 to 40 degrees. It implies a certain percent going to lift and the other to forward propulsion.

In the vid he's most likely got the wind behind him. Whatever it was speed wise can be deducted from the total speed so 100 mph is not impossible for a 300 or 450. Scale that up and it's going 20 times a full scale one to one. Compared to a 700 (average 130mph) and the 450 scaled up speed is around 200mph. I'm basing the estimation on chassis length, 450=24" and 700=48". The 450 is one half of a 700 in length.

Ya know, Peregrine Falcon have been clocked 200mph in a dive, that's fas.

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08-10-2013 05:03 PM  4 years agoPost 27
Luvmyhelis

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Spokane, Washington. USA

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Like I said, the smaller size is no limit to how fast these can go. I hit my times last spring. That is swinging 420mm blades on a lightweight 450 framed heli using a virtually unboggable 12s motor. The mod list was extensive and the heli in no way resembles anything stock. (I wrote a long post detailing out some of it and deleted it all) I figure most guys don't want to know how it is done. Just the results.

And in answer to a post above about the pitch corkscrew effect. My heli was running 13.8 pitch with an unboggable motor in a feather weight frame. My dual swash coaxial version has a $800 one off German machined head on it, and will be using a counter rotating pusher prop.

Plus I did two extensive write ups about the 12s 450 over at RCG and Helifreaks last year. All I got out of those write ups were a couple educated idiots trying to tell my why 12s isn't more efficient. In spite of my half hour flight times and extensive testing results.

Old cranky heli builder

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08-10-2013 10:11 PM  4 years agoPost 28
icanfly

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ontario

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half hour flight times and extensive testing results.
You mess with these things too? lol

The coax sounds very interesting. You have the same name at rcg and hf? I'll search them. Most experimenting gets scoffed at 'cause they didn't do it first when it's successful.

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08-11-2013 05:12 PM  4 years agoPost 29
Luvmyhelis

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Spokane, Washington. USA

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Yeah, also over at RCG. I got a permanent time out over at HF when I was helping with the early Warp project. I was asked to run the official Warp mod thread. And had a few unkind words to say about it as I went through that heli. Even though Compass is now using parts I designed on their heli. A few of their advertising reps got upset and had Will freeze my account.

The Coax project is on a Vtail brushless mod thread on RCG. I even burned my own gyromixer for it. But I quit posting up about it when I sent the head out eons ago and haven't gotten it back yet. The smaller 250 sized dual swashed version was so bloody fast and nimble I honestly could't fly it at the skill level I had at the time. Imagine a heli with 5x faster piro rates and able to flip over on itself outside of its cog. With dual heads commanding the same axis change. Crazy stuff.

The big thing with coaxial design. Is the lack of the tail rotor. Anything back there can be used for propelling the heli instead of producing drag.

There is alot to play with on these that also have much to do with speed runs. All my ultra light 600 based 700 plus stretched helis are much faster than my true portly 700s. The canopies take forever to carve out.

Old cranky heli builder

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08-11-2013 05:22 PM  4 years agoPost 30
stubbs

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Tuscon, AZ

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A few of their advertising reps got upset and had Will freeze my account.
So, if you desire, set up another one with a throw away email address.

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08-11-2013 05:30 PM  4 years agoPost 31
RCHSF

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NC

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A few of their advertising reps got upset and had Will freeze my account.
stubbs
So, if you desire, set up another one with a throw away email address.
I'm sure they block the IP.

Might be away around that thought, never played with that stuff.

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08-11-2013 05:48 PM  4 years agoPost 32
icanfly

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ontario

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Cool, I saw what you did with the raised tail 6s thing on rcg, your right into these things. Want to see something interesting?

I discovered quite by accident what can cause a little instability in the rotor and swash degrees. Here's how it began. I wanted to lighten my heli and strip off every undesirable weight possible so I began drilling lots of parts, swiss cheeze-ing them. First was the tail, the block, then non structural things like the boom support mounts, then the blade clamps, and onto the head itself. I then redesigned my landing gear with alu and drilled the back of all my alu case mg servos. I have a metal base which will loose half of it's size and weight if I fab a cf one and redesign the lower frames. Essentially I'm prototyping out a new heli out of an old one.

Here's my guideless mod, and it works more than well,

The gyro plate is gone now ( an Ar71BX would eliminate the rx)

Much cleaner, simpler, and an added bonus just so happen to be a little retard of the swash events which stabilized the heli better than stock or advanced. WHY? Here's my theory. When your heli is compensating for the tail pushing the heli to the left the swash has induced aright pitch. A slight delay in the swash events means that the blades do not flutter. They probably do so because as they are in a constant state of right pitch they would have to return to zero in the rotor rotation and back up when you give it added right pitch. This would introduce flutter, and or introduce a harmonic. I saw my heli wobble a bit and the gyro chase the wobble when the swash was advanced by half a degree before I made another guide with the retarded position.

Another cause of instability in a heli is that as the tail is pushing to the left in a cw main rotating assembly. It is offset by the boom so the tail will rotate the heli in a long arc if unchecked. By negatively degree-ing in the swash it actually will counter act that effect without over working the gyro. Never considered these things but what I'm learning from trial and error can be transferred to a nobar heli one day.

LMH, Unfortunate what happened in the Compass scenario but NEVER go to the little people and expect a helping hand. I've learned to hold back and go to the top or keep quite till you can. Some ideas aren't worth a lot, and some are golden. Those are the ones you want to keep close to yourself, the little fish are plenty. The pics I've shown are of things that no one would really care about but they do say I'm a guy who really plays with these in more than the flight aspect, as you appear to be also.

The heli of mine is very stable and very flyable I'm happy to report. Just a half degree retard (late) could stablize the heli that much to be noticable, even piros are more controlled, whoda figgered, yahooee.

BTW, I could eliminate the rx and associated wiring with a satellite.
stretched helis are much faster
I was thinking that myself, probably because the tail works better to hold it in undisturbed air rather than the turbulence at the main tips when in forward motion (the tail has to fight through).

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08-11-2013 08:44 PM  4 years agoPost 33
Luvmyhelis

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Spokane, Washington. USA

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Interesting work! I know Helihaven uses the elev or center servo arm to lock the link into a straight up down control link for the swash. But none of us looked into your theory. Shoot, you should have seen the flamers that viciously attacked when a few of us did some testing with that raised tail concept. And proved the right hand skid lean was virtually gone. Same deal on the 6s/12s stuff I did all those years ago when the industry was still only 3s in the 450 class. It was unbelievable. I now call those guys educated idiots. All they had was opinion and theory. Not a single one had actually tried any of it.

Old cranky heli builder

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08-11-2013 10:20 PM  4 years agoPost 34
icanfly

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ontario

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I saw some ytub vids on the raised tail/ main disc leaning situation. It does make things more complex though I know there's a thing called "coupling" that will make a heli balance very well.

A long time ago they used to make degree-able swash plates. I know my swash is now 1 degree late.

Interesting ya, if you look at the old se frame and pitch servo between the frames you will see a tail block rod between. I put another at the set of holes above the servo, where the old guide used to be, to yet again stiffen the frame, it works.

I had originally used the pitch servo link as guide but knew I could go one step further. The new guide (flange at the top) keeps it closest to the swash as possible and I went through the full servo range to fine tune things.

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08-16-2013 10:39 PM  4 years agoPost 35
icanfly

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ontario

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had to give up the roll axis swash follower and go with the elevator again, here's the new one like a mini hockey stick. It's more stable, solid, and crash proof plus the elevator only goes up and down and not sideways like the roll servos do a little.

While I was having fun I decided to reshape the tail rounding it off some. looks nicer and is slightly lighter, but mainly because I've aired out most everything aluminum, lol

The practice of holes was my first on this heli, didn't turn out too bad really though all the holes were done/set/placed by hand and a wandering drill bit, haha, so they're not perfectly centered anywhere.

FAS?

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