The only comparison I can make, yet again with my model heli's, is that learning to fly mine with it tethered was much harder than allowing small hops across the field. I also had the benefit of two wooden rods forming an x under the heli to widen the footprint and thus stop it rolling over. My thoughts would be in the middle of a nice big field, and then do small hops till you manage to hold it in a steady hover.

Good luck.

Si

I think it is best to slowly pull it off about 1 inch and then set it right back down before it starts to move sideways or backward. Keep doing that until you can hold a 1 inch hover without moving. Then go a bit higher.

But I am no expert. Expert instruction would help.

Bournmouth , I see that pic has the provisions for the optional radome :ok:

Nice design!
Why have you changed the previous round Tailboom to a square section tailboom?

And don't listen to those who've never flown microlights - they're not used to real flying or minimum standards.

Happy New year and the best of luck.

Rigga

Hey rigga, 'Minimum Standards'?? Wanna bet? PMSL

May I hover it?

I'm only up the road, Halesowen. Got a PL(H).

Cron

balls
 

hi !

I owned and flew the deathtrap revolution mini 500 !
If somebody knows what he is doing experimentals can be ok.
but said that, i did not know what is was doing, had just 70 hours and fortune to fly the mini a couple hours and then sold it to complete my CFI.
the mini`s with a turbine must be a blast :} !

fly safe - happy new year !

Rick

Bug, Have any of the previous bugs flown?

I watched a homebuilt hover around a field a few years ago. I seem to recall it had a Yamaha 2 stroke bike engine and flew well till it lost a tail rotor blade!:eek: - no one hurt. I dont know if the builder was a Ppruner - I think he might he may have been called Julian. He might be able to help if anyone on here knows who he is and can put you in contact.

Like others I am curious to know why belts were chosen over shaft and gearbox for the TR when youve got the power to lift the extra weight. That said, I dont think the Rotorways have too many problems with a belt drive TR.

Cheers.

BTW, I have flown a few machines over the years straight after major overhauls, rebuilds, crash repairs etc. (certified only). I do it from concrete to reduce the chance of a skid digging in if it starts to go pear shaped. I'd rather rotate or slide sideways than roll over. Spend some time with it at flying rpm and no collective pitch, check the disk moves as expected with cyclic input. Check the tip plane of the blades is not split. Pedal inputs should cause the aircraft to move slightly, again as predicted. You can feel the thrust just twisting the aircraft a bit. When happy,apply a little collective to get light on the skids and check the pedals make sense again. Check the tip plane of the MR blades. If they split with added collective pitch expect vertical bounce in the hover. This is best checked with a strobe and tip targets. Be very careful with cyclic inputs when light on the skids. Be prepared to dump the lever. When happy, go light on the skids to get TR thrust balanced and pull into a low hover. Be prepared to dump the lever. Take it carefully. Probably best to practice this quite a bit and get it hovering right before moving on to any other tests.

Over the years, I have come across assembly, rigging and tracking and balancing problems with aircraft straight out of maintenance. So far the above technique has worked and nothing has got damaged. Its pretty obvious if its not right. The test is aborted and the problem solved. Others may do it differently but this works for me.

Are my balls big enough for the bug? I might hover it but after that you're on your own.

Best of luck.
Phil

I have five radio control helis, and the least of them looks more formidable and complicated that that machine. Seriously though, if its been checked its got to be as safe as any other machine. Dont tell me that professional heli pilots are falling into the civvy assumption that larger is safer?

"we breed 'em tough and fearless here"
 

Bug - Love your attitude!! Go for it man, and as for "...or should i go for the full monty and just grit my teeth?" Grit your teeth, but for goodness sake, don't get carried away and do something you may later live to regret (or worse, you don't live to regret)!! I'd spend a looooong time at a very looooow hover and doing lots of very gentle manoevres before ding anything that could really bite you.

Best of luck with it - would love to come and help if you need another pair of hands!

TTB

Bugdevheli - I can see where the belt design does have major advantages regarding weight saving, and elimination of the gearboxes, driveshafts & universal joints. I would trust that the belts are aviation grade Kevlar, and not automotive grade.

Belt whip is something that probably needs to be addressed - the distances between the pulleys are quite long, and to eliminate dangerous whip, there are only two ways to do so. One way is to increase belt tension substantially - thus leading to belt stress, shorter life and increased likelihood of failure. The second way is to add idler pulleys to control whip. A third way would be to increase the number of pulleys overall, and thereby reduce the individual belt lengths.

Does this thing actually get off the ground? I haven't seen a video of it actually hovering. I don't believe that too many previous test hovers of chopper prototypes, saw them tethered. Tethering seems like it would place outside forces on the chopper that could lead to incorrect presumptions of stability. Far better to let it fly free, and gather inputs that precisely reflect true flying conditions.

My last question is - what are the plans for a proper fuel tank? - and wouldn't this thing have a very limited range? The weight penalty of a decent fuel tank would seem, to me, to be a big bugbear in the design.

Rigga - From an engineering viewpoint, square sections have vastly increased strength over round sections, when it comes to load-carrying capacity. The sharp corners of a square profile increase strength enormously over the simple round section.

P.S. I've got a thick skin, feel free to savage me all you like, if you feel my comments are too critical. I'm trying to offer constructive criticism, but different people have varying opinons, as to when constructive criticism ends, and destructive criticism starts.
I must say I agree with BoeingMEL, you cerainly look like an old and bold pilot to me. Good luck.

"and wouldn't this thing have a very limited range?"

Its range potential is a moot point as it won't be doing anything more than hovering and maybe a sly CAA unaware circuit, IF anyone's brave enough.....

Please correct me though if you know better and think it would be issued a Permit to Test....

PD

The photo with the rather splendid little heli bug being under the "Deutsche SeeKonig" gives a good example of just how small small really is, the tail rotor of the SK is much much larger than the main rotor on the Bug.

But I still think I would have enough joules to slightly unstick from terra firma, done with much deftness I am sure the traits for such a tiny thing would soon be learnt, after all if most of us can fly the R22 then we are already used to twitchiness in the extreme, I think wind speed and gusts would prove the greatest area of problems for one so small.:eek:

Peter R-B
Vfr

I note that the main concern has been dealt with ... the BROWN corduroys!!!:E:E

Do not tether it !!!!!!
 

Tethering it will cause more problems than its solves.
I own and fly fullsize but have flown dozens of my own model helicopters in the early years when power/stability were big problems.

A good idea for first flights would be to simply increase the width of the undercarriage [sideways and for/aft] with lightweight beams to prevent rollover. pref with rollers at extremeties.

Good luck. Dont like the idea of belt drive to tail however. Never good on models. Shaft drive only way for power and reliability.

OOW

Onetrack

Is that true? Most of the super structures built today use round tube over box section, including the new rooves over Wembley stadium and Wimbledon, as well as the 2012 Olympic stadium. I'm not an engineer, but if square section is stronger, why don't all helis have box setion tails :confused:

TTB

Comparing round and oblong beams, I though "total strength" (all directions) was unchanged but whereas round has equal resistance to any direction of distortion, oblong is stronger to specific direction but the penalty is reduced strength to others.

Not an engineer, stand to be enlightened

if only i had the balls to try it
 

Gentlemen, gentlemen, I really do appreciate all you comments, both positive and those of a more piss taking nature. I am old enough not to be plauged by the impertinance of those still wet behind the ears. Life is so short and must be lived to the full. I allways tell it as it really is. someone asked ," have previous bugs flown". Bug 1 hovered on its first trial (on tethers) Bug 2 was an attempt to utilise composites in the skid bow and body structures. Bug3 was built to encompass lessons learned during manufacture of MK1 and MK2. This machine now currently resides in Portugal and is currently being test hovered by its new owner. Bug4 was untill yesterday undergoing a rigorous ground test proceedure during which i managed to bugger the sprag clutch whilst doing start up proceedures. (sometimes all the calculations are disproved during actual use). Tomorrow, well, lets wait and see. (if we could still work in pounds and feet, and stuff we really understand, then life would be much easer). I mean who the bloody hell invented Newton Meters. Foot lbs. Twelve inches to the Foot. sounds logical to me "to be continued".

I have to agree with Gaseous's post, even a Super Puma or Sikorsky S61 just out of heavies sometimes isn't immediately airworthy. The idea of ground runs then working each control to check reaction is a good one.

Always think what's the worse that could happen and prepare for it at all stages, then when it doesn't happen you can laugh yourself all the way to the pub.

Si

TTB - Nearly every design project is torn between strength and weight, from an engineers viewpoint. In many cases, weight saving is crucial, and round section often provides adequate strength - whereas the strength gain from box section is often badly offset by the weight gain. Cost also comes into the equation, with round section often considerably cheaper.

bugdevheli - I presume the sprag clutch engineering calculations didn't include adequate shock load factor? Nasty stuff, that shock loading. Did you know that a load suspended on a crane hook, if suddenly dropped 2", will almost double the load on the hook/cable/boom/jib? Yes, I must confess, I like the old feet, inches and ft lb stuff. I must be as old as you, I certainly have nearly the same amount of white hair ... :)

Hey one track,

I have in my pocket 2 Florins, and 1 half crown, not many folk remember those, or know what value they are today!

Peter R-B:ok:
Vfr

vfrpilotPB/2 - Ahhh, yes - florins and half crowns - but can you remember buying threepenny ice cream cones?? :D :)

Entertaining thread, well done one and all. The spouting off by people who clearly don't know Bugdevheli, or "Julian" or the abilities of either is really amusing to the few on here that know both of them.

Go for it, Bugdevheli.

Andrew, a friend from years ago, from when the Mini 500 still showed promise.

all i need now is the balls to try it
 

Andrew. Thank you. Its been a few years since we met. J is alive and well and married (just in case you did not know). He and she are both qualified and have their own aircraft Regards you know who.

Hey Andrew, It was me that mentioned Julian and there was no criticism implied. If its the same person, he's smart. He was developing a remote controlled tracking device to adjust the pitch links in flight and he once tracked my Enstrom with a chadwick. I only knew him through John Dunn and when John died I didn't see Julian again. His homebuilt flew brilliantly. People like him and Ben are to be applauded. :D:ok:

Bug - outstanding! It's people like you that put the "Great" in Britain! I would love to see it in a low (safe!) hover. The very Best of British to you.

Gaseous, I didn't think that you were being critical, I am just amused that people just...... Well you know what I mean.

Bugdevheli, I didn't know that J and Y had got hitched. I actually tried to visit him recently (3rd Sun in November) as I was in his neck of the woods. He had gone to see you for the weekend! I am up to date on his flying activities and their Wittman Tailwind. My heli licence is a bit lapsed now but I am still flying often. I have gone all "plank", I have two 3 axis microlights, one which I built from a kit, and we have just ordered another kit from the Ukraine. Must sell at least one aircraft to pay for the next one.

keep me posted, Andrew.

onetrack - understood re dilemma of balance 'twixt strength and weight of tube vs. box section - makes sense. As for threepenny ice cream cones, yes - i remember them rather too well, along with tanners and coppers :sad:

I also clearly remember making my very first purchase - a Mars bar, c. 1963 and costing the princely sum of 3d... Ah, those were the days, etc...

Bug - we're all dying to know what the next step in the plan is - if there is one :)

TTB

Has anyone tryed using a felxible drive for the rail rotors yet?

I have seen it many times on RC helicopters and never heard of any failures

A larger variant will make for a system with many less parts with high tail gearbox setups

Run the shaft through a bent sleve lined with nylon. As long as its correctly lubricated, I dont see why its not a good idea

Any thoughts?

Simon :ok:

My first purchase was for a tanner.

I gave the lady a bob and she offered a pair of threepeny bits in exchange.

T_D

Who bonded the blades?
 

OK I'll ask my obvious questions based on my usual themes: Are the blades bonded? If so by whom? Using what adhesive? After what surface preparation process? How were the bonds cured?

Same questions for the composite structure joints.

If the answers involve ACME and Wylie Cayote I'm outa here!

Regards

blakmax

Perhaps this product might offer the soution?

Bulls Balls®, Big Boy Nutz™, Original Truck Balls™, Truck Nuts, Truck Nutz, Bike Nutz & Bumper Nuts.

Not sure of the weight penalty!:eek:

bugdevheli - Don't worry about risking your neck any more - I found the guy who'll volunteer for the TP job. He's the right size for your cute little machine, and suitably outfitted in the cojones dept, as well ...... :)

http://i48.tinypic.com/11qhf6r.jpg

all i need now is the balls to try it
 

Onetrack, he is obviously a squirrel pilot. I have it on good authority that they are all endowed in a similar manner. Toptobottom. When i have proven the Bug airframe and drive systems, i plan to construct a full size ring rotor a mockup of which can be seen on one of the pics posted (the mock up sits on top os a pair of blades) The ring rotor is device that permits enormous inertia without the weight penalty of heavy blades. My belief is that until these VLH machines have loads of inertia they are risky at best, and deadly in low level operation, particularly the sort of flying carried out by low time pilots.BUG.

IMHO, there's a lot of cock talked about "aircraft quality", especially when it comes to GA and LAA /experimentals.

Often it comes down purely to the traceability (paper-trail)

Those "automotive quality" drive-belts (flat, multi-vee) are extremely durable,"fit and forget" items.
The longer, "serpentine" ones follow a convoluted path,sometimes with more than a 180* wrap round pulleys of~8-10cm diameter, driving water-pump, aircon-pump, power-steering pump,alternator and cooling-fan....all fluctuating loads at fluctuating speeds in an engine going ~900rpm to~ 7000 rpm. life-expectancy is often 100,000 miles +without failure or maintenance.

that tail -drive with balanced-loading on both sides of the boom (limited float needed to even-out inequalities between pairs) seems a simple, elegant,low-stress,low-maintenance tail-drive solution,

Model Helis using a similar toothed-belt to that employed in computer printers, are extremely reliable and the Raptor series,using that drive has been the most popular mass-produced kit for a fair while.

Glad to see someone with the courage of his own convictions not letting the nanny state suffocate him.

the jobsworths would not have allowed the Wrights to fly, nor the first hang-gliders.

Aviation at this level sems to have thrived on innovation outflanking the beaurocrats with their control and legislation.

Bravo!

All i need now is the balls to try it !!!
 

Well all i can say is , if you have had the Balls along with the commitment and passion to build, design and engineer it then im sure you have the balls to fly it!!!
How wonderful that there is still someone out there with a true passion for design,engineering and flight, if it were not for people like you we would never have had the light bulb! the first tv! or indeed the first form of flight !!!!!!!
well done and keep up the good work anyone who cannot see the time and effort gone in to this machine and the commitment from yourself to it is obviously stupid.:D

Sorry, been busy on other stuff...
 

Bug,

A lot of carefull thought has gone into this machine. I'm guessing that you've done some testing on those skids to make sure they absorb energy for various scenarios. That rotorhead / swashplate looks like an engineering story in itself - one i'd be interested in hearing. Do you have any closeups of main rotor, tail rotor, control mech and rest of machine? Unless you are worried about disclosure of design etc. Looks like some interesting drivetrain around the (Triumph?) engine. Are those more belts hidden between those two aluminium plates?

The thing that astonishes me is that this was all designed by one person! Looks like many man-years of work. All you?

Just remember that every new engineering project is a collection of faults just waiting to be discovered. Take every opportunity to check that fatigue is not gently accumulating cycles (i know you've done FEA) and that wear is not gently rubbing away contact. Check every bolt torque as often as you can (vibration & joint movement) and look to see that those belts haven't picked up any FOD. Definately check welds very regularly - with die penetrant if practical.

BTW does the rotor / drivetrain have enough inertia without the ring-rotor for <2 seconds of flight with no power? Talking with the many (always extremely helpful) test pilots on Rotorheads i get the impression that the key is to carefully think out what the objective of the each flight is then figure out the absolute minimum risk way to achieve that objective. Sometimes that may involve sitting down for a cup of coffee.

Just my £0.005...

This would work with a lightweight Turbine, in place of the Piston job! one of the Prune Rotorheads quite possibly has just the thing plus the knowledge! :ooh:

Peter R-B
Vfr

all i need now is the balls to try it
 

Graviman and peter RB. Just a clarification! One of the photos posted shows the mk 3 machine which has a ring rotor device mounted above its normal pair of blades. This was done just to expose the ring rotor concept to interested parties at an airshow. The actual ring rotor will be fifteen feet diameter. The Ringrotor is something i have been working on, to provide great inertia with a minimum weight penalty. The Mk4 has been designed so as to be able to retro fit the ring rotor when airframe and drive systems are proven.This is why the tailboom lenght is adjustable. The current engine is a Yamaha FZR. I will post some closeups of bits you mention. Thanks Bug.

Ah, it's a Yamaha FZR. Which size? I'm guessing you went with a 1000 but run it derated - not sure how many thousand miles of motorway speeds/power motorbike engines are designed to last these days. Helis seem to aim for a few thousand hours at least.

I like the concept: figure out the single main obstacle to making helicopters safe, rotor inertia, and then design a rotor specifically to improve this feature. And as a side benefit improve the aerodynamic efficiency by a potential maximum of 30% for a given rotor diameter. This one deserves to succeed!

Normally rotors are tested on top of whirl towers. Why not firmly bolt the whole helicopter to a balance, maybe out of ground effect, then "fly" it to check the performance? Or strap it to a weighted trolley (heavier version of your castored wheels on the skids) to keep it on terra-firma while you pull collective to what would be hover for a series of ground runs to get the feel of it? If you are sure where the C of G is then you could mount heli to trolley with four ball joint end links converging just above CG (for stability)*. Best if ball ends attatched to the fuselage, as close to C of G as possible. Use a scissor link (or drive shaft with sliding splines) to make trolley follow in yaw.

This would give you the feel of the machine in flight but without putting yourself at risk. In particular, confidence that the machine is behaving itself dynamically, including tail rotor and main rotor in flap-back. If you check all of the bolts, welds, belts, etc after each run you will prove to yourself that the machine is reliable.

Just a thought.


*I originally suggested tethers, but these would cause problems as they became taught. Also they do not allow various collective settings to be tried.