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Prop strike


Guest francis777
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Ever had a control handle or throttle cable strike the prop  

11 members have voted

  1. 1. Ever had a control handle or throttle cable strike the prop

    • yes no damage
      1
    • yes prop damage
      1
    • yes flight safety impaired
      1
    • yes injury sustained
      0
    • no never
      8


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I am compiling stats on control handles or throttle cable entering prop disc or penetrating cage.

If you would pm me any details of these incidents I would greatly appreciate it.

I will not publish equipment specific results but will give general stats and feed information back to manufacturers privately.

motor make and model

any modifications

details of damage

time, place, flight plan details

wing

harness hang option

all helpful in compiling this.

Thanks

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Re: Control handle prop strike - The story so far

Raw Data so far:-

11 pilots reporting 15 incidents between 2004 and 2008.

1 fatal (cause n ot determined; symptomatic of wrap and wind-in)

1 pilot-safety severely compromised but disaster averted.

8 damage reports. Minor prop damage (repairable nicks) and control

handle damage (sliced off; magnet cut off)

Little data on netting size from reporting pilots,

Limited data on hang point type but examples from both.

Little data on BHPA memebership or whether reported.

3 examples of incidents in training (no indication of whether

reported).

2 instances of throttle control stike.

Discussion Topic..... Would a fine mesh net eliminate the danger? Is

reliance on "Park the Brakes" briefing adequate? What do/will the

Germans do?

REPORT SYNOPSES:-

Manchester Pilot control handle chopped off by the prop. (2nd hand

report)

Northern Pilot training flight inturrupted by a buzzing noise saw

handle grazing prop and gingerly pulled it back

through netting. (2nd hand report)

Cheshire Pilot had a tip take control handle on aborted launch; let

go of control trying to kill engine. 1st training flight attampt.

(1st hand report)

Pilot 2007 (Speculation) symptoms of loss of control consistent with

control wrap and wind in. Fatal.(2nd hand report)

Lady Pilot 2004 in training handle prop strikewhen she released the

handle to try and get into the seat soon The prop strike slashed off

the magnetic clip. Contributed to decision not to continue

training.(2nd hand report by spouse)

Pilot released control soon after take off to assist getting into

seat and control struck prop. No damage reported

Same Pilot reports a second identical incident prompting ammendment

to his procedures. These occurred after changing from high to low

hang point machine. (1st hand report)

Scotland Pilot preparing to take off dropped handle unintentionally

conincident with slight wing tuck resulting in prop strike. No Damage

reported (1st hand report)

Norfolk Pilot throttle control prop strike. Damage to kill switch. at

altitude on cruise control throttle on my knee, slid off, prop struck

it at the bottom of the cage. prop tip damaged. (1st hand report)

2004 Pilot released controls unaware that the brake handle had gone

through the cage. the glider dived violently to the left, diving at

ground. control line wrapped the prop and wound it. Released itself

somehow. Pilot survived after regaining control. (1st hand report)

Ireland Pilot 2006 released right control to assist getting into

harness after take off without parking handle. Minor Prop damage;

handle exited cage immediately on being struck. (1st hand report)

Southern Pilot 2006 released left control without parking. Control

struck prop. Slight prop damage.

Same Pilot reports identical incident on same machine using different

wing in 2007

Same Pilot reports identical incident on different machine from same

manufacturer in 2008 prop damage and control magnet sliced off

Same pilot reports different machine and different wing throttle

cable prop strike during take off run. Prop damaged and plastic

sheath to cable slightly damaged. (1st hand report) (yes its me folks)

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I now have over twenty control handle prop strike reports three involving serious hazard to the pilot and two of these in injury.

Throttle cable strikes are less frequently reported; 3 in total.

Most of the pilots who could be contacted have expressed the opinion that a fine mesh over the cage would have prevented ingress of the handle or the cable.

Three reported the ingress to be around not through the cage.

Reports have been on a selection of the common machines but there is insufficient data to assess the frequncy in any machine or hang point type.

Machines that have 50mm netting provided no protection in the reported incidents according to the pilots interviewed.

Three reported incidents occurred in training on a "school" machine or under instruction.

All contact has been by email and pm and relied on pilots' integrity.

My conclusions:

Risk assessment:

I think that the risk of wrap round and wind in is too high to rely on pilot briefing of "dont let go the handles and park the brakes".

Motor yaw and pitch can reduce the gap from handle (even parked) to prop to zero or less. This is particularly dangerous on take off wriggling into your seat! Or when "on-bar" cruising and weight shifting.

Low revs are potentially more likely to result in wrap and high revs in "sput out"

Risk mitigation:

I will fit 1 inch netting to all student machines and offer it as an option on all sales. I am looking for a strong (hand unbreakable) monofilament net that can be cable tied or sewn to manufacturer's netting or to the cage frame. (any suggestions? upholsterers net?)

Discuss with manufacturers these findings and request redesign.

Table a question at the forthcoming Safety Seminar. Discuss with the Germans at same to establish vot zey do?

I am using gardeners bird netting initially but this is not quite strong enough, although should be UV resistant.

Please continue to post reports and even if you are not a member please submit an incident report to the BHPA (post paid) who can collate the statistics in the long term.

http://www.bhpa.co.uk/pdf/IR10_06.pdf

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I just had my first hour on my Brand spanking Macro coupled with an airwave sport 3. Wow what an incredible hour.

Anyway back to the thread. I am a convert from hill flying.

My major concern was how to get into the harness whilst holding the brakes and throttle.

I let go of the brake on the right and it stayed right next to the pulley on the riser.

I let off the other brake and again it stayed next to the riser directly underneath the pulley. I looked up at the canopy and realised that because I was already at trim speed = pressure in the wing.

The brakes are pulled to within 5cm of the pully and could not get pulled back into the prop. I presume this is a feature of low hangpoints. A pulley placed where the brakes normally rest at trim speed should cure the need for magnets etc.

I can see a problem on the same wing, if I had High hangpoints and no pulley further down.

Just my thoughts on my flight around buckinghamshire lastnight

Simon :D

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Glad to hear you had a great flight and agree the Macro is a superb machine.

But I would love to disabuse you of your conclusion regarding the brake handle.

Your observations of the set up is quite correct there is no way the handle can reach the prop disc even if not parked.

BUT if you induce a yaw in the motor (it twists in the risers) and/or you tip the p[rop disc forward at the top (e.g. legs outstretched or on speed bar) the prop disc can meet the rear riser and munch the handle even if parked.

Always park the brake and be careful into movement and weight shift, observing the effect on the disc behind you.

I have done this to my upper cage. Not pretty but effective.

17042008(002).jpg

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Hi Francis

You are dead right, These movements could cause armageddon. during my hands off flying and seat getting in, I try and keep everything in equilibrium, makeing all movements slight.

Your cage seems mod seems a great idea, even if the chance of a problem is small. You will have no problem.

what we need is a cool netting with the logo written into it, to keep with the lovely design of the beast

cheers simon

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On my harness i have an old speed bar fastened to my seat by two lengths of string, this means the speed bar is just dangling about 12 inches below my seat, just after take off i pull my seat forward under my bum using my foot on the old speed bar, my hands never let go of the brakes or throttle, it's 100% effective!

An instructor came up with this idea and fastened it on for me way back when i was learning because he was also struggling to get into the seat on take off.

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I dont have to use my hands to get into my harness and never have.....

I think if a harness is adjusted correctly that the action of lifting your knees to your chest will slde you into place with little to no effort.

I have had high and low hang point, old and new motors.... never had to use my hands to get into a harness.

SW :D

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I note the point that Norman made about units tightly strung with fishing gut or kevlar line may also gain strength. Something I have thought about for a while now and have been looking at the Flat-top paramotor by RPMPPG. I've been writing to Bill who builds them and he is soon to ship a couple over if anyone wants a look.

The Walkerjet , I'm flying currently, seems to swallow me into the seat too quickly. But I have been farming for 28 years and subsequently cant stand up straight.

I haven't had a prop strike whilst airborne but I feel it worth mentioning that the plastic clip on the end of the chest strap got sucked in and smashed against the prop whilst breaking in the motor on the ground a year ago.

Dave

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