Paulipod

Hey Derek... a little off to mis-quote sections of my text by ommision! If I was to do the same from your post I could quote... I'll have a try at the same maybe... ... hmmm I can tell? - not nice huh. -------- That aside - my point is that alot of input is made into this kind of discussion with no real experience of the situations. I doubt that nearly all posters in this topic have ever actually experienced a real power outage. Press E or turning down the power is not the same. This is where I see the discrepancy. Both the throttle and e-stop are simple control inputs to the VFD. The VFD then responds in a controlled way with gradual speed change. A power outage to the VFD is totally different... and something I would be surprised if hardly anyone has seen an most faclities. I do not need to have flown in SVCO to know or understand this.... but if it matters SVCO / New Hampshire / Airkix / Orlando / Perris / AZ all use the same control + Drive + VFD technology which I have experienced first hand and at other non-SV tunnels Mostly just wanted to emphasise the point that this is something that I am very sure about... I think a few of the posts previously are based more on guesswork rather than experience or science. My purpose here is not one of trying to piss you off - say that one tunnel is better than another - say that any tunnel is not safe.... just merely stay with the physics facts of the situation that all facilties are faced with!

Ok... just because the fans can be reduced in speed (electronically - by the VFD) doesnt mean it has a braking system in the mechanical sense of the words. As has been said the VFD can reduce speed through resistance. I dont care what any of you say about inertia of wind and the fan blades... bluntly - I think you are all wrong if you think that a spinning fan with no power and moving wind in a circuit have any possibility to sustain flight. Given the size and weight of our drive system - the winding down time - the amount of moving air - I think we would notice some benefit if this were the case and our power went off! I have been flying in a couple of tunnels and been dropped 6ft with a change in outside wind direction or pressure loss through doors etc.... let alone having no power on! lol And - to be a little bolder... I will happily put my money where my mouth is if any of you are confident enough for a wager

I would be greatly surprised if the solution there has Brakes! As far as I understand (and I look at this technology alot) The solution at all of the R12's from Skyventure are powered by VFD units direct to the Flak-Woods fans. The Flak-Woods fans are simple direct motor supply - no brakes in there. You could argue that running the motor on less power acts like an electronic brake if the power change was quick... but non-the less that is not a braking system. It is plain simple wishfull thinking that a power outage would not be noticable - and if you think otherwise I can say with a degree of certainty that you havent experienced one. Bottom line is - it takes around 300KW to 500KW of power to move wind fast enough to sustain flying in an R12 when there is 0KW you cant fly (quickly) and the amount of intertia/potential in the non-powered fans is not even worth mentioning.

Thanks :) The boys arrived at healthy weights of 7lb8oz and 7lb - Which is quite good for twins! here they are - and clearly have my boyish good looks Bodyflight Bedford www.bodyflight.co.uk

Quite worrying really.... Bodyflight Bedford www.bodyflight.co.uk

ROFL - dont be silly... do you know how much that kind of network link costs! - they never go wrong Bodyflight Bedford www.bodyflight.co.uk

Sadly its impossible to guage from public accounts whats really going on with any company - especially in startup years etc... otherwise I would have subscribed to alot of account data before we started for sure! lol I think the sucess of tunnels vary greatly... its not always the bed of roses that everyone thinks - but then again certainly attractive enough to make alot of us want to give it a try. After all it is Nirvana to find a business that you can make a living and also really love.

Not sure this is correct - As Eule said... its not the same turning the speed down on a regulated controller to the VFD losing power. Bottom line is - if you put zero power in.... you have zero lift. Inertia of small turning blades is tiny... Inertia from our prop for example at 5m you think would give some lift - but with the power turned off would struggle to dry your hair. Bodyflight Bedford www.bodyflight.co.uk

Almost instantly... Having been in the situation a couple of times (in different facilities) the result is like going into instant freefall. Although the fans still spin for a bit - there is a world of difference between just spinning down and the many hundreds of horses in normal flight.... Takes you by surpirse thats for sure! lol

Hiya! Hopefully managed not to bore you too much with the geek stuff! Bottom line is - if the power goes off.... we all fall down! As far as I am aware, a power outage in every tunnel built to date will result in almost instant air loss. For this reason we make sure the net is more springy than not... and also that our power supply is as protected as possible. Power backups of the size needed are not at all cost viable.

There are a few pro's and con's for either multiple or single.... Considerations for multiple :- 1. More 'off the shelf' availability 2. Offers a little resilience - ie if one of 5 break you may still be able to run. ... although in most SV designs losing a fan will seriously affect air quality 3. VFD technology for speed control is ALOT cheaper for 250HP or less... and more reliable 4. It is harder to ensure the same frequency etc of multiple Considerations for Single :- 1. Power range of prop technology is greater (ie.. our prop ranges to over 4000HP) 2. Less moving parts... larger bearings etc... 3. Drive is less affected by loading / ie flyers in chamber etc 4. Variable pitch more feasible on larger units Just a few - the decision can be made on many other factors too

Mulitple or single fans above the airflow dont make any difference to the laminar flow of flight chamber.... but does remove the turbulence from blades etc as you say. This design has been used in scientific facilities since the late 40's as it is the best way to achieve a good test flow. 'Dead spots' against the wall would be caused by frictional losses on the walls and openings like doorways.

I would bet that you would have a video that would be worth around $500 for appearing on the 'Worlds most shocking accidents' programme Bodyflight Bedford www.bodyflight.co.uk

[URL]www.bodyflight.net[/URL] has a list of all current tunnels In Europe we have a few to play in Bodyflight Bedford www.bodyflight.co.uk

And we are also always looking for ways to get involved in helping English Totty Bodyflight Bedford www.bodyflight.co.uk

Not likely as you would expect.... However not being able to recover is not necessarily due to the backflip manouver itself - just general flying in the tunnel and learning stability/control will help with your recovery when unstable. In short - you wont be doing flips - but its likely to help none the less

As far as I understand (from several people I know that have visited) The existing Bragg tunnel is capable of speeds around 150mph and has a motor somewhere around 3000HP - at 14ft in Diameter - also freeflying is not a problem in there... seen alot of photos which show this too Always good to see facilities evolving to new levels... Bodyflight Bedford www.bodyflight.co.uk

I would think that for belly speeds this may be OK - would certainly start to struggle if you wanted freefly speeds (over 150mph) if we had another 2 ft diameter. (that extra diameter is a shit load of area!!) It is not a linear curve of power to diameter but power to volume.... the more area the power needed increases significantly. But also efficiency of the airflow etc make a large difference too. For example drawing in outside air to cool can make maybe a 20% power difference... or as in our case passing the air over heat exchangers loses power too.. Also how many fliers! and I am guessing the idea would be to increase the number of people also!! But - On past performance you know that these boys are doing their homework... and to be fair I havent seen a single skyventure tunnel to date that has not flown. So maybe we should let them do their own calculations

hehehe.... yeah as all our instructors will agree (internal joke - sorry peeps) Bodyflight Bedford www.bodyflight.co.uk

Hi, There is no real way to predict until we see you fly.... but provided you are both stable and in control (ie not looking like you are about to hit each other / walls etc and maintain your fall rate) We will do our best to get you in there together - and from what you have said you will more than likely be OK Only other thing that may play a part would be your weights... it takes a little more practice to have a good range of fall rate and your friend may need to wear lead if you are different sizes... but again we will advise on this at the time and do our best to have you flying together.

Awww... if you are in that kind of mood it would be better just to call samaritans ps - I have been taking the piss out of Nigel since before it was fashionable Bodyflight Bedford www.bodyflight.co.uk

Nah - it just goes to show that we are an equal opportunities employer Nigel is our token bid at care in the community Bodyflight Bedford www.bodyflight.co.uk

I think you should trip across the pond too - may as well make a full set! We will add tunnel time if you make it this far Bodyflight Bedford www.bodyflight.co.uk

Damn... I'll have to start calling our tunnel the worlds largest tunnel in Bedford Bodyflight Bedford www.bodyflight.co.uk

If you fancy a trip over the pond we'll welcome you with a big