Blade 700 Spindle Bolts 4mm? Really?

[Auger]

I was thinking about picking up a new Blade 700 and was perusing forums and the manual when I happened to notice the spindle bolts are 4mm, I hope this is a typo as that seems a bit small for a electric 700 size machine spinning 1900-2300 rpm.

After noticing this I started to consider the safety aspects of this and felt it might be a good idea to discuss this a little. To help put things in perspective 4mm spindle bolts have been known to fail on 600 size helicopters.

The thread length is listed as 12mm as well, by the time you take off 1mm for the washer and 1mm for tolerance (china) that leaves approximately 10mm left as thread contact area, with the proper materials being used this is probably adequate but cutting it a little close. Overseas suppliers are not known for using proper materials and possible internal defects can help to magnify the issues.

After nooticing this I also ran into the recall on the spindle washers and considering the head of a 4mm bolt is 7mm od and the blade grip bearings are 8mm id once the washer deflects the angular loads placed on the bolt are going to be excessive and the 8mm id bearings will have clearance over the 7mm od bolt so there is nothing to keep the grip from coming off. The od of the spindle bolt should always exceed the id of the grip bearings to help distribute the forces properly and support the washer as well.

Just some thoughts on the topic, my decision is an easy one on this and I'll just look at other brands using 6mm bolts.

I suspect there is either a new spindle in the works for 5mm bolts (or soon will be) but that also leaves the concern that there is only 3mm of spindle left at the ends to support the outer grip bearings and considering the threads are cut into the spindle, in addition to the hardening process in that area that leaves questions of the spindle shearing next.

Not really recommending flying or grounding in any way, but please consider this when flying your heli and keep safety in mind. Damaging a model heli is really minor in comparison to an injury to yourself or someone else.

On all helis keep it above your head, keep the head speed reasonable to help reduce the loads and avoid over speeds as much as possible. I unfortunately have seen some blades and grips come off over the years on 60's through 90's and its not a pretty sight. After hearing the 12 gauge gunshot sound and watching the blade fly 600ft through the air at 100mph+ you begin to respect the forces involved.

We did get away with 4mm spindle bolts on 60's and the original 90's but that was at lower head speeds (1750-1900) and well before the new beat the crap out of it 3d style (I do this as well) and high head speeds (I don't do this). The repetitive stress on these bolts is tremendous and even if you get away with it for a while ultimately its going to become an issue. At this point even with bolts we feel are the correct size for the model I have a tendency to replace the spindles and bolts at least once a year just to try and avoid the problem.

Just some thoughts, safety first.

[soljkaer20]

I understand your concerns. The spindle bolt is more than adequate in this application. It has been stress and life tested to ensure that is satisfactory. There is 10 mm of threads in the spindle after the washer. Safety is a very big concern of ours and that is why we recalled the washers as soon as we hear some reports of the deforming.

Thanks,
James

[TomC]

Originally Posted by soljkaer20

I understand your concerns. The spindle bolt is more than adequate in this application. It has been stress and life tested to ensure that is satisfactory. There is 10 mm of threads in the spindle after the washer. Safety is a very big concern of ours and that is why we recalled the washers as soon as we hear some reports of the deforming.

Thanks,
James

I still do not feel 100% comfortable with this. I do not know of any other current 700 heli that does not use a 5mm spindle bolt together with 5mm main blade bolt (like the 700x also uses). Even my +7 yr old Ion-x uses both.

Maybe the few bending issues of the 700x spindle washers is due to the smaller 4mm spindle bolt head diameter? I have never heard of this issue with any other current 700 heli.

Just my opinion but I would like to see Blade go to a 5mm spindle bolt.

Cheers,
TomC

[jimmy77611]

This is troubling to me. I have the money and desire for a 700 size heli, and am struggling to figure out which one I want. I love the looks and features of the Blade 700x, but I think I get what is being said here.

I've owned several Blade helis, and always felt like they made certain parts a little less than the quality that they could be. Be it canopies that break so easily or landing skids, frames, etc that break really easily on the micros. I've often felt like they do this to either sell more parts or cut costs in manufacturing.

On a micro, cutting costs or making things not beefy enough probably won't kill someone. On this 700x, someone could get injured badly or die.

So my question is, on all the other 700 helis out today, we have the bolt head AND washer keeping the blade grip from ejecting, but on the 700X we have to rely only on the washer?

[OnTheSnap]

Interesting topic. Here's a snapshot of the Blade manual:


And from a 700e:


Pretty dramatic difference between a M4x12mm and a M6x16mm.

I trust the engineering here. But this is the first time I've seen this on a 700.

What's the maximum recommended blade size and headspeed on this model? If I choose to run 2400 rpm with 700mm blades would it be OK?

[crashcopterman]

Originally Posted by Auger

I was thinking about picking up a new Blade 700 and was perusing forums and the manual when I happened to notice the spindle bolts are 4mm, I hope this is a typo as that seems a bit small for a electric 700 size machine spinning 1900-2300 rpm.

After noticing this I started to consider the safety aspects of this and felt it might be a good idea to discuss this a little. To help put things in perspective 4mm spindle bolts have been known to fail on 600 size helicopters.

The thread length is listed as 12mm as well, by the time you take off 1mm for the washer and 1mm for tolerance (china) that leaves approximately 10mm left as thread contact area, with the proper materials being used this is probably adequate but cutting it a little close. Overseas suppliers are not known for using proper materials and possible internal defects can help to magnify the issues.

After nooticing this I also ran into the recall on the spindle washers and considering the head of a 4mm bolt is 7mm od and the blade grip bearings are 8mm id once the washer deflects the angular loads placed on the bolt are going to be excessive and the 8mm id bearings will have clearance over the 7mm od bolt so there is nothing to keep the grip from coming off. The od of the spindle bolt should always exceed the id of the grip bearings to help distribute the forces properly and support the washer as well.

Just some thoughts on the topic, my decision is an easy one on this and I'll just look at other brands using 6mm bolts.

I suspect there is either a new spindle in the works for 5mm bolts (or soon will be) but that also leaves the concern that there is only 3mm of spindle left at the ends to support the outer grip bearings and considering the threads are cut into the spindle, in addition to the hardening process in that area that leaves questions of the spindle shearing next.

Not really recommending flying or grounding in any way, but please consider this when flying your heli and keep safety in mind. Damaging a model heli is really minor in comparison to an injury to yourself or someone else.

On all helis keep it above your head, keep the head speed reasonable to help reduce the loads and avoid over speeds as much as possible. I unfortunately have seen some blades and grips come off over the years on 60's through 90's and its not a pretty sight. After hearing the 12 gauge gunshot sound and watching the blade fly 600ft through the air at 100mph+ you begin to respect the forces involved.

We did get away with 4mm spindle bolts on 60's and the original 90's but that was at lower head speeds (1750-1900) and well before the new beat the crap out of it 3d style (I do this as well) and high head speeds (I don't do this). The repetitive stress on these bolts is tremendous and even if you get away with it for a while ultimately its going to become an issue. At this point even with bolts we feel are the correct size for the model I have a tendency to replace the spindles and bolts at least once a year just to try and avoid the problem.

Just some thoughts, safety first.

We used to clad ourselves in thick metal during battle, now we have light jackets that will stop even more potent weapons. It's not necessarily about 'how thick' or 'how big' a fastener is, metallurgy is an amazing science and material composition is more important than strictly fastener size in this day and age.

[Allen_H]

Lol I don't think that applies where this stuff is coming from.

This message was created using a mobile device all terms are subject to change.

[jimmy77611]

Seems odd that they would choose a small bolt for such a critical spot. I've downloaded the manuals for a few other 700's I'm looking at, and only one uses 5mm. The others use 6mm!

[raisinjack]

boy some of you guys really amaze me on how you can take off on a subject.

just go take a look at the size of the cone bolts that hold the JT8-219 engine on the pylon of an MD88, I swear you guys would sh! t at the size of them also.

[jimmy77611]

Originally Posted by raisinjack

boy some of you guys really amaze me on how you can take off on a subject.

just go take a look at the size of the cone bolts that hold the JT8-219 engine on the pylon of an MD88, I swear you guys would sh! t at the size of them also.

IMO...Nothing wrong with discussing a feature of a brand new product, especially when it deviates from the industry standard, and appears that it could be a potential safety hazard.

I'm sure the JT8-219 had some pretty extensive engineering and testing, much more than the Blade 700x.

If anything, I'd like to see Blade come on here and explain WHY they chose to use 4mm for the spindle bolts, if it is a design decision. Otherwise, why wouldn't they have just emulated the industry?

[crashcopterman]

4mm x .7 pitch bolt in grade 8.8 will hold about 1500 pounds-tensile.

[Brian James]

Originally Posted by jimmy77611

IMO...Nothing wrong with discussing a feature of a brand new product, especially when it deviates from the industry standard, and appears that it could be a potential safety hazard.

I'm sure the JT8-219 had some pretty extensive engineering and testing, much more than the Blade 700x.

If anything, I'd like to see Blade come on here and explain WHY they chose to use 4mm for the spindle bolts, if it is a design decision. Otherwise, why wouldn't they have just emulated the industry?

I understand its a brand new product to you and the rest of the industry, but we have been flying it for many months. the hardware is within spec for the application, and quite simply it works. There really is no need to fabricate a potential problem when there is none.

[TomC]

Originally Posted by Brian James

I understand its a brand new product to you and the rest of the industry, but we have been flying it for many months. the hardware is within spec for the application, and quite simply it works. There really is no need to fabricate a potential problem when there is none.

You are probably right Brian but using the same M4x12mm spindle endbolts on the 700x that is also used on both the 550x and 600x heli's begs to question why Blade decided to go this way.

Exp. since all other current 700 heli's using 8mm spindles (like the 700x) are using 5M endbolts and those using 10mm spindles (like Align 700e) use 6M bolts.

If you want to stray from current industry standards, yet still want to price it with the big boys, do not be surprised to see people questioning this. Imho I think Blade should simply replace these 700x endbolts with M5x10-12mm bolts (maybe even flanged ones) if only to prevent the potential misconception of a potential problem.

Cheers,
TomC

[OnTheSnap]

Originally Posted by TomC

You are probably right Brian but using the same M4x12mm spindle endbolts on the 700x that is also used on both the 550x and 600x heli's begs to question why Blade decided to go this way.

Exp. since all other current 700 heli's using 8mm spindles (like the 700x) are using 5M endbolts and those using 10mm spindles (like Align 700e) use 6M bolts.

If you want to stray from current industry standards, yet still want to price it with the big boys, do not be surprised to see people questioning this. Imho I think Blade should simply replace these 700x endbolts with M5x10-12mm bolts (maybe even flanged ones) if only to prevent the potential misconception of a potential problem.

Cheers,
TomC

+1

There is design and there is marketing. In this case whether it's OK with 4mm bolts or not, marketing wise it's probably not a good choice.

[raisinjack]

Originally Posted by jimmy77611

IMO...Nothing wrong with discussing a feature of a brand new product, especially when it deviates from the industry standard, and appears that it could be a potential safety hazard.

I'm sure the JT8-219 had some pretty extensive engineering and testing, much more than the Blade 700x.

If anything, I'd like to see Blade come on here and explain WHY they chose to use 4mm for the spindle bolts, if it is a design decision. Otherwise, why wouldn't they have just emulated the industry?

nothing wrong with a discussion,but theorizing is another. Hell just flying these things(rc helis) could be a safety hazard in many peoples eyes. The original premise here is that it just" doesn't look right" therefore my post about the engine mount bolts because if you saw them you wouldn't believe they do what they do,merely because it doesn't look right.

Why do they have to emulate the industry? And show me the industry standards that the manufacturers have to follow. Do we need or want an FAA style rules making body hovering over us? Setting standards and monitoring compliance over all of us?

[crashcopterman]

Originally Posted by raisinjack

nothing wrong with a discussion,but theorizing is another. Hell just flying these things(rc helis) could be a safety hazard in many peoples eyes. The original premise here is that it just" doesn't look right" therefore my post about the engine mount bolts because if you saw them you wouldn't believe they do what they do,merely because it doesn't look right.

Why do they have to emulate the industry? And show me the industry standards that the manufacturers have to follow. Do we need or want an FAA style rules making body hovering over us? Setting standards and monitoring compliance over all of us?

Standards.....pfffffft!!!!!!! haha

And people bitch about prices now, imagine if a governing body was involved!!!!

[OnTheSnap]

I wonder if any other heads are a drop in fit? Just in case you want the 6mm bolts. (-:

[TomC]

Originally Posted by OnTheSnap

+1

There is design and there is marketing. In this case whether it's OK with 4mm bolts or not, marketing wise it's probably not a good choice.

I think this is a very wise statement that Blade would be very wise to consider imho.

Originally Posted by OnTheSnap

I wonder if any other heads are a drop in fit? Just in case you want the 6mm bolts. (-:

Don't think you would want 6M bolts on a 8mm spindle since it starts to get to be a pretty big spindle bolt hole. Only the 10mm spindles (like Align 700/800) use a 6M bolt.

It would be a shame if this seemingly minor issue (to some), on a very nicely designed heli, ends up costing 700x sales.

Cheers,
TomC

[Auger]

To put a little perspective on what I was thinking about when looking at the manual see the attached picture, its free so no complaints on the quality or spelling When you look at things along the lines of stress risers, force vectors, and contact area its a little concerning.

Even if I get past the 4mm bolt being enough the deflection of the washer is a major concern. Washers are meant to be compressed evenly, not deformed in such a way. The bolt in this case is much stronger than the washer, but the washer is taking all the force involved.

Keep the head speed reasonable until someone puts the proper amount of effort into analyzing this, I am up to an hour and this would really take several weeks to work through everything.

Blades are heavier now and the weight is further towards the tip bringing the centrifugal forces up considerably higher than the #'s I have shown plus higher head speeds, more power and aggressive flying styles steer me towards thinking this could be an issue, just my opinion and I really hope I am wrong on that.

Be safe....
Brian

[Brian James]

Originally Posted by Auger

To put a little perspective on what I was thinking about when looking at the manual see the attached picture, its free so no complaints on the quality or spelling When you look at things along the lines of stress risers, force vectors, and contact area its a little concerning.

Even if I get past the 4mm bolt being enough the deflection of the washer is a major concern. Washers are meant to be compressed evenly, not deformed in such a way. The bolt in this case is much stronger than the washer, but the washer is taking all the force involved.

Keep the head speed reasonable until someone puts the proper amount of effort into analyzing this, I am up to an hour and this would really take several weeks to work through everything.

Blades are heavier now and the weight is further towards the tip bringing the centrifugal forces up considerably higher than the #'s I have shown plus higher head speeds, more power and aggressive flying styles steer me towards thinking this could be an issue, just my opinion and I really hope I am wrong on that.

Be safe....
Brian

Let me clarify further. Fortunately, you are wrong. This is not an issue. It was designed by talented engineers properly, and is not helpful to anyone when people start rumors.

It is common when a designer does not understand how to engineer with material selection to oversize fasteners resulting in bulky, overweight components. This ultimately leads to perceptions that certain fasteners need to be of a certain size.

For example, you can build an impenetrable wall of marshmallows if you build it thick enough. With a properly selected material, such as steel in the case of this wall, the wall can be much thinner and lighter and accomplish the same goal. Make sense?